You know, Endeavor is right.
In a world where people are born with genetically inherited superpowers, why shouldn’t you breed out the imperfections in them? There is nothing wrong with this goal, given it is something that makes it easier for your children to live/have better lives than you, by given them less inconvenient powers/limitations.
Take his own quirk, it makes it so when he uses it he overheats. It’s likely that before he trained it, he overheated at much lower threshold than his current abilities (due to all the training he has done, he has pushed his limit much higher than it was before due to his goal of reaching All Mights level, he trained all the time. And we’ve seen what just a little training can do for a quirk). We have seen that training a quirk is necessary to make it useful, especially for those with such strict limitations/hard to master like his (see Kirishima, who had to smack himself with blunt objects a lot before even being able to attempt to enter UA, or Denki who can’t use to much power of his power or else he’ll go brain dead, or even Midoriya, who can’t use OfA without almost dying, or Black who’s quirk was original just to merge into black things, but after training it, can now move those things).
It only makes sense to try to make it so future generations wouldn’t be burdened with useless/harmful to themselves powers, and anybody who actually disagrees with this is selfish; the betterment of society as a whole override your own happiness. Couples should be forced to match up with the most compatible other quirk user so that society can quickly breed out the imperfections inherent in quirks to make everything advance in the fastest direction to perfection (this the best decision because some families would undoubtedly start doing this anyway).