Hux being upset that he has to play strict dad because he thinks his daughter doesn't love him as much as she loves Kylo. And in a way he isn't wrong, their daughter clearly favors Kylo because she knows Kylo won't say no to her or tell her the rules.
This sounds like my parents when I was younger. My Mum was so strict that she had a go at my Dad because he was he ‘fun’ one who never said no to me and Mum was the one who always told me off.
So I can totally see Hux being annoyed that he’s the responsible one who’s disciplining their daughter when Kylo just seems to be messing around.
But I also know that my Dad was that way with me because both of his parents were terribly strict with him so he didn’t want to be that way with me. So maybe Leia & Han were strict on Ben so now Kylo doesn’t want to be that way with his daughter.
