I guess Horikoshi thought Hawks hating Enji made no sense or something. Because he portrayed him as such a fan boy of Endavour, and maybe he thought if Hawks came to hate him, it would be anti-thesis of Endavour developing himself for the better and make his redemption arc kinda pointless?
We know that the members of Touya family, especially Natsu, had negative reactions toward Enji even after his redemption but they suffered in that same household, so it makes sense for them to resent Enji.
Meanwhile Hawks was kinda sympathetic to Shouta but besides that, he wasnt personally affected by that situation, so it was easier for him to ignore and focus on Enji's current/present situation as an individual.
Ok, I take issue with a lot of the points you made here.
,"it would be anti-thesis of Endavour developing himself for the better and make his redemption arc kinda pointless?"
First, let's not talk about "redemption" in the case of Endeavor. He himself acknowledges that what he's done to his family is beyond forgiveness, and he can only strive for atonement. Second, atonement is not done for present/future reward but to try to make amends for past sins. So Endeavor shouldn't be rewarded by anything to atone - his ledger is already very red. He needs good deeds to balance those. That's the point.
2. "Hawks was kinda sympathetic to Shouta but besides that, he wasnt personally affected by that situation, so it was easier for him to ignore and focus on Enji's current/present situation as an individual."
This doesn't make sense because Hawks is a hero. A hero doesn't need to be personally affected by a situation - they should be able to distinguish injustice and fight it. That's kind of the point of a hero. Hawks (and every single other pro-hero) shrugging off Endeavor's exposed crimes with a "this doesn't impact me" makes them all look bad, people without any moral integrity, who will protect one of their own no matter what horrible things he's done to innocent victims (sort of how cops will protect often the truly despicable among their ranks).
The fact that Hawks himself is a victim of child abuse makes it even weirder. He should be able to personally empathise with the Todosiblings.
Sometimes I see in fandom those fans who were themselves victims of DV / child abuse looking at Endeavor and thinking "I wish my dad tried to change" and that's valid. But Hawks is not even put into this kind of mental position, but rather into comparing himself to Shouto, and blaming himself for leaving his own abusive parents behind.
The point is, in Endeavor's "atonement arc", the burden is left disproportionately to the victims. Endeavor becomes a better hero (but he was already good at his job, so it's kind of pointless in the context of atonement), but he's not able to do much for his family beyond buying them a house that doesn't even get used much.
He never manages to put his family first, to step up for them in any real way. Rather, it's the family who is constantly put in a position to prop up Endeavor:
Shouto saves his life (both in the PLF war and in the final war), steps in to fight when Endeavor can't or won't (Ending and Dabi both times), catches strays for Endeavor's past behaviour (Inasa)
The family props him up emotionally in the hospital after the PLF war because the situation forces them to
If they want to try to save Touya, they have to save Endeavor with him
They are made to share the responsibility for Touya's spiral, to the point of getting "karmic scars", including Fuyumi who was a child.
And what does Endeavor do for them? How does he step up?
He doesn't. All the narrative focuses on is to support the perpetrators and give him rewards for trying to be better, while not providing support to the victims, not providing justice to the victims, not taking a strong stance on right and wrong, and certainly not rewarding them.
It's kind of a sad irony how Hawks, who himself was a child abuse victim gets character assassinated to prop up Endeavor.
