I think a lot of these people - a depressing number of parents in general, really - liked their kids when they were cute little babies and toddlers who didn’t have their own opinions or demand privacy or whose boundaries and personal autonomy could be more easily over-ridden because you can pick them up and tote them around.
When you have a baby, you’re very much the center of that baby’s world. They’re completely dependent on you.
But once the kids get older and start being more opinionated and having more complicated feelings, and don’t just idolize their parents, and maybe start to realize their parents are flawed human beings just like every other human who’s ever existed, and you can’t just stuff them in a foofy dress or whatever to make them Be Cute on command, there’s a certain kind of parent who feels very offended and threatened by that.
It’s like when your kitten or puppy grows up to be an adult cat or dog, and they’re not “cute” anymore.
And that’s when a lot of shit about “earning your keep” starts, and a lot of the guilt-tripping, too, I think, when kids don’t just fall down at these parents’ feet in gratitude and obeisance.