Bro this is the NV, if you want to talk about the real world then discuss it in the general discussion section. Even in the real world those who have power and those who don't aren't equal except in that they are born and they will die.
Power has nothing to do with what I am saying. What I'm saying, is that clans like the Uchiha and Hyuuga shouldn't care so much about whether or not a child is "pure blood" or whether or not a descendant's last name is Uchiha/Hyuuga. I'm saying that they should just focus on themselves, and let that other person be.
In other words:
You say that, Hinata/Boruto/Himawari should have gotten the seal, but I say Hiashi should have just let them be (which he did). He shouldn't care whether or not Hinata took the last name Uzumaki, nor should he care whether or not some non-pure blood descendants have byakugan.
Just let them be. If they have byakugan, fine. If they don't, that's also fine.
Similarly, I have also seen you and/or other Uchiha fans say something to the effect of "Sasuke should have had a son, because Sarada is a female and would take on some other last name", or "Sasuke should have married Hanabi, but sealed her genes so that the child could be pure Uchiha".
I am saying that it shouldn't matter to Sasuke or anyone else whether or not Sarada's hypothetical future child bears the surname Uchiha, nor should it matter whether or not Sarada keeps the Uchiha name, because either way that child would still be Sasuke's grandchild, and he should love them anyway.
Similarly, even if Sasuke did marry Hanabi, he shouldn't care to seal her genes because he should love his wife/child just because they are his wife/child. The purity of their Uchiha blood shouldn't mean jack. Race doesn't matter, and the care about it is what perpetuates racism and discrimination both in the real world and in the manga/anime world.
Short sum-up of my view point:
Let's say one day 30 years from now (in the manga, not the real world), there exists some random child named Jack Jones who happens to possess the byakugan and the sharingan due to some mixed ancestry. It's perfectly fine. Nobody should bother or attack Jack for this, or ostracize him in any way.