To be perfectly honest (and I know that this would get me called a heretic by those who make a really big deal out of the finer details of tea), but I didn't forget to note any of them other than fermented teas- I simply rolled them into their general categories, since they don't really deserve a separate category themselves.
White teas as a category (rather than sub-category) don't really exist since they're really not much more than an even lighter green tea preparation done to leaves initially picked for black tea (so you get the more mature leaves' profiles as well as the young buds used in both categories), being then baked and lightly rolled instead of steamed and rolled as is done for greens. They are the most impacted by cultivar variety used within the family of green teas.
Oolongs are much the same as a sub-category rather than category in that they're basically black tea in process that is oxidized for a variable duration rather than fully oxidized, such that oxidation can range from near-green to near-full black, giving it some green tea notes that vary based on that level of oxidation, while otherwise being a black tea.
Yellows are the least deserving of their own category, as they are just green teas that are steamed for longer, which makes the chlorophyll break down and become a yellowish green, the source of the yellow colour of those teas; I don't even consider them a proper sub-category.
Lastly, fermented teas; young fermented tea is basically just green tea, since that's what it is before it gets prepared for fermenting, and the fermentation process hasn't changed it sufficiently from the original product. The fermentation process also is an oxidation process (resulting from outside influence rather than the tea's own enzymes), & the microbacterial/fungal processing breaks down some of the compounds and creates new ones unique to the fermentation process form of oxidation (in large part through free radicals), giving it a distinctively different flavour, and the processing is sufficiently different that it does deserve its own category, so thank you for pointing out that I forgot to mention it. That said, any Sheng puerh is by definition old, considering its has been fermented for a long time to even reach the designation of "Sheng" to begin with; only thing I can think of that you're referring to for a "young Sheng" is the green tea base used to make fermented teas. Shu puerh is just the same base of tea "Mao" (the unoxidized green tea base I mentioned above) used for Sheng, but artificially ripened to be ready in months rather than years, basically treating the maocha like compost and monitoring the moisture content and temperature, mixing it every so often so it doesn't develop the wrong kind of mold that likes really moist tea.
Now, finally, addressing tea varieties aside:
I said that black teas are always bitter up-front. This doesn't mean that they don't have more complex flavours behind the bitterness, just that the first taste to touch your tongue will be that initial bitter shock. I also didn't say that "only green isn't bitter at all", I said, and I quote, "Only green tea isn't guarenteed to be bitter at all, but can still have some bitter notes due to the catechins and tannins, still; here is where cultivar really matters to differentiate.", emphasis mine.
No, even if it's exactly as bitter as I expect it to be, or even less, bitter is still bitter. Being a supertaster doesn't help in that respect, sure, but getting the depth of the tea after that initial bitter shock is always a delight.
There is a lot wrong with what you said here
Fermented teas while similar are vastly and appreciably different from one another due to how they are fermented, their preparation and storage, they do deserve categorization, especially Sheng and Shou puerh, since those are too very different things
White teas are their own thing entirely, it is often sun dried, and it has their own range of flavors ranging wet hay, stewed cherry and of course, nearly always honey (greens tend to be more vegetal, herbaceous or nutty, I've had tomatoey greens, piney greens, and greens that taste closest to any other type of veg)
also the way of preparing green and black teas varies vastly between the type that is being made, some times black teas are rolled like greens, sometimes greens aren't rolled.
That you call Oolong a sub category is plain ridiculous, people, especially in the west like to try and force oolong to fit between green and black as a middle point/ mixture. This is wrong, very wrong. Oolong is perhaps the type of tea with the MOST variations, whether through preparation or varietals used, though the two big ones are charcoal roasted and those which aren't, but that's just scratching the surface and oolong alone eclipses the forms of three types of tea, black, white, and green in the many, many ways it is made. It is not a sub category, at all, to be simple and concise. But suffice to say, they are not basically black tea, if you've ever had a cup of oolong, this would be obvious
Can't say anything about yellow tea, since it is hard to come by and I haven't had it since my favorite sellers don't keep much of it in stock
And this is even more outrageous? Young fermented tea is like green tea? No it isn't. The taste is entirely different, the way it is steeped and created is entirely different. And the claim that fermenting it hasn't changed it, is just plain nonsense. You WILL know if you got given a young Sheng Puerh rather than green tea, you will know if you've been given an aged sheng instead of green tea, and you will defiantly know if its shou, aged or not. But this claim seems to be a misunderstanding of terminology, so allow me to explain myself.
When I say Young Sheng, I mean Sheng which hasn't been aged as Puerh for long, this is the standard way of referring to it, everyone who is into puerh does it, its how it is marketed by the sellers, and the farmers who they get it from. Some people by cakes to age themselves, some only drink Puerh stored in certain regions, it is a whole thing. It is called Young for years after production and fermentation, Until its astringency mellows with age. You are however right about shou, it was made to basically speed run Puerh but not for time, it was to try and mimic the taste of Aged Sheng, which is at least seven years old by usual measures. Not to mention tea makers get experimental with the leaves they use to make both Sheng and Shou, it isn't just what is used for green tea, but generally and traditionally, that tends to be what is used
And I have drank enough black tea to drown small nations, unless it is over steeped or made in the English method (which by design will make it bitter, since using as little tea as is generally used in western brewing, to get any flavor you must steep it for awhile, and that in turn, allows more of the bitter chemicals to leech out into one brewing), bitterness is not the first note on the tongue. It depends on the tea what that is, some are much more predominantly sweet, some are what I'd call dry, and others have more roasted/ malty notes. But unless you're using broken leaves and or brewing it the british way, it will not have a bitter shock.
And Ignored that bit about not being guaranteed bitter, cause its wrong
No tea is guaranteed to be bitter, cept young shengs and that's a sliding scale. Broken, mulched leaves will be bitter, but no varietal or form of tea is bitter by nature besides it, so green tea, naturally, is not an exception to a rule that doesn't exist.
It really just seems you've googled most of this, cause of how much you focus on the production methods and how they're similar rather than what the tea actually is and your vast misunderstandings of the varieties of it, especially what young sheng was, but to be fair, that is the realm of gong fu nuts like myself, and just reading about Sheng and Shou wouldn't explain that and neither do most "What is puerh" blurbs that sites make to try and hawk what they claim is puerh to ignorant masses (I will burn harney and sons to the ground for what they sell as Puerh, that stuff had a mouthfeel of dust and a taste of sun baked seaweed and decayed sealife, it was an utter abomination, and I drink shous that taste like stewed oak wood!)
Green and white are close yes, but are much more different than they are similar
Oolong is so vast and varied its nearly ripped itself free from the rest of tea, its insane how varied oolong is.
