I mean we already at least know about his stance with his own father who simply wanted to save Eorzea. (And we know how that would have ended if he was not there?) Alisaie also does not talk that greatly about him either, saying that he barely even stayed in contact with his kids. And now he was shown as someone straight up disowning his children while others are there too.
I think it should be quite reasonable that not everyone still likes him and thinks of him as an awesome person.
Of course people are complex but that does not mean that we have to like them or think that they are great. Even the worst real life people will have something sympathetic if you dig deep enough but that does not mean that this suddenly outweights their actions.
Just like how Yotsuyus past might have explained her a bit more and gave a more complex story behind her actions but what she did was still absolutely horrible. (I also have a hard time seeing people comparing Yotsuyu and the twins dad. Not liking a character because they acted like a jerk and wanting to teach him some kind of lesson is not the same as saying that he is on the same level as the woman who mass murdered and tortured countless of Doman people)
I mean you also dont like all the characters in the game. Graha is a recent example. Someone that also only got a major role with Shadowbringers and that after 5.3 has to find his place in the old world. Yet its quite fine to wish him death even though his own character arc as the new Graha just started while we cant go and say that we simply dont like the twins dad because right now he is a jerk?
How many people disliked Alphinaud because he was a stuck up brat in ARR? Were they wrong too to dislike him at that moment? When are we allowed to like or dislike a character? Maybe sometimes the view will change with more story later but maybe he will be just a jerk at the end.