I'm so sorry for the essay, but I really love Yuri and want to make a point in its defense.
Yuri manga has come a long way in the almost 20 years I've been reading it. Homosexual manga in general were always regarded as "perverted or deviant" if the characters acted on any desire for the same sex, it could also be considered hentai even if it was just a kiss! It used to be that bad! So to get your homo manga published, you had to keep it entirely subtext, or keep it totally chaste/pining from afar, or sacrificing your gay feelings for the other person's hetero happiness, or everyone's fave just bury your gays. The only way you could get more explicit lesbian stuff was in self published doujins. I can still remember surreptitiously googling for English translations of these rare doujins (doropanda-tours, anyone?)
Now that LGBTQ sexualities are becoming more accepted so are the manga. We get to enjoy Yuri manga that isn't intended to punish the gays with suffering, yay! But now that Yuri is "mainstream" it's becoming profitable to exploit it, fetishize it, same as with hetero manga. I actually can't stand non-yuri relationship manga anymore because of the stupid and offensive set-ups a lot of them have! Why are like 50% of them harem stories with MarySue protags that can do no wrong and have no personality or flaws (coughSwordArtcough)? Bleegh. And no one seems to have any problem with those guys because they take straight couples for granted, or they want to be that guy. The guy never gets punished or has to change, except to become 'sexier.'
But I would say for the most part Yuri manga does not suffer from this. It just seems like it does because there is so much more variation in Yuri stories than there was 10 or even 5 years ago. So while I understand why people are concerned about the influx of "problematic" Yuri premises, I think this is a good thing! You *should* have discretion when reading works that actually encourage predatory/criminal behaviour or trivialize victims. But if a story starts with imperfect characters, who are put in situations where they want to change, then learn and grow from their past mistakes, I think the story will be all the better and deserves a chance.
Remember, manga are serializations; unlike novels you don't get to see the whole journey in one go. Not all Yuri manga are going to be stories where women sexually harrass each other for laughs or edge. Realize that blackmail and harassment are bad, but don't say a story is bad just for showing those things. One of the great things about fiction is you can be exposed to things outside your comfort zone without having to experience misfortune.
You are not a bad person for NOT liking blackmail stories, as long as you're not trying to demonize anyone who likes the thing you don't like. You are not a bad person FOR liking stories with blackmail set-ups as long as you understand why the thing is bad, why you shouldn't actually do it and how absolutely unlikely it would be for doing that thing to result in you getting a hot, kind girlfriend. [The exception here is pedophilia. I will never understand why someone would want to creep on children, or pretend to creep on children, or creep on someone who looks like a child. F@#k those people absolutely, forever.]