why people care too much about the nickname (mom/dad)

i don't know why people salty about how taeho didn't call the parents mom or dad. i mean it's murim manhwa what do you expect? they have position in the cult and it's not something simple as others family you have read in the other stories.

why focus on that, when taeho alone said that he's happy and didn't care about the "nickname". they're happy family and i don't know why you guys can't see it. maybe it's the first time you read the story that didn't called their parents with mom or dad