Males in that world is the product of their circumstances.
A severe imbalance of male to female ratio (1:39) would have, eventually, lead to the circumstances you can see in their modern world.
if you have looked into the R18 version of this, you would have seen than all 3 family members are admitted virgins. Not too surprising for Sakura, but the mother and older sister is surprising by "Our" standards/RL standards. Older sister is most likely either at college/university age or even older. The Mother has birthed 3 children. But they are all virgins.
Considering the fact that there is a government program for early birth and support for that birth (along with a bonus of birthing a male), there is an active effort to try and fix the ratio. This is done via artificial insemination due to the mother being an admitted virgin. This is hampered by, what is logically sound conclusion, quirked genetic anomaly in which the human race births more females than males.
Now imagine that society before the discovery of the techniques for artificial insemination. Either the world has a big difference in population numbers vs "the real world" (on an order of magnitude lesser than "the real world") because of the sheer DEMAND increase numbers "the manual way"... Or there is what is essentially a farm. It is quite horrific to imagine to live as a male in that circumstances.
However, survival as a group/nation requires these measures before the techniques of artificial insemination is discovered. Even then, however, it doesn't take away the sheer sexual drive that humans have innately to engage in such activities. With the large competition to tap on a source, it would have driven females (in both a biological sense and societal sense) to be hyper sexual in such a persuit because doing so will ensure that you "win" biologically.
You can go down this rabbit hole while exploring the biological, societal, and historical implications of the contexts given in this work of how that world came to be.
At the end of it, as a critical thinker, I just can't help but be horrified for humanity as a whole to be in that circumstances. I know that as a manga work, these circumstances are turned light hearted and made into tropes as you pointed out (even tho as tropes go, I feel that you're still missing the mark for all the other males vs MC-kun) . Imagine yourself being in that shoes tho. You have females who have a mindset of hyper sexuality as a default both biologically and societal/mentally (remember that the girls who we have been shown in the school are SUPPOSED TO BE THE ELITE and are expected to have a massive amount of control over their libido). Your gender most likely has been historically has been forced (one way or another) to impregnate multitudes of women which births to more women and some males (which will be subjected to the same circumstances when they are able to produce semen). Only at modern times has your "duty as a man" switched from "overworked breeding bull" to "splat your semen into a cup".
Now I'm not a man but I have a critical thinking brain. I'll reiterate it: THOSE IMPLIED CIRCUMSTANCES ARE HORRIFIC BUT IS DONE FOR THE SURVIVAL OF THE SPECIES. Is it any wonder why the males in that world is "so different" from the typical male in "the real world"?
But the author wouldn't have thought about it this hard. These circumstances are played for laughs and jokes but it still irritates me than people seem to genuinely think that males in that world are just "beta cuck soy boys" or some "lesser" of a man because they are "pathetic" or some other combination of adjectives.
Is it fictional people? of course. But I can't help but have that thing blaring at the back of my mind because of how easy it is for circumstances like that to happen when thinking of it logically.
Whew. Anyways...
The males here are more implied to be more "Yaoi" than anything else; wanting to bond with those in similar situations as themselves and relate to each other on the shared "suffering" they are all going under. On some cases, they are fans of yuri just like the male that MC-kun saw in the train and the thought of "getting inbetween the love of two maidens" is sacrilege. I saw that spoiler'd before.
Remember on how the "all boys school" was looked at and spread the logical conclusions from there.
In terms of MC-kun... I feel that he might be thirsted on by many females... but he'll keep his "real world" mindset and be monogamous (just like most of the typical romcom harem works). It is a god damn waste and most likely he'll end up being attacked sexually.
Considering the hints of what the typical male-female relationship is in that world, a harem is the typical, not the exception. However, with how "exceptional" MC-kun is in that world, the author might just run with that "exception" and thrust him into a monogamous relationship.
it is the expectation really for these kind of works. At least the MC-kun isn't a total and abject dense as a blackhole loser who doesn't even listen to the outright words being said to him. Like... I mean... none has sat him down and told it to his face...
Some MC's will have the people around him declare their undying love for him and show utter devotion but will hold off because "he doesn't look like anyone special" (aka doesn't have a pretty boy face). -insert "You dense motherf*cker".gif-
... huh. I had time to type that out... Time to take a nap.
