I read it more as wry irony. "My dad was dumb and wrong, but I'm totally right when I feel the same way he did." I don't think the comment really means either one of them was right or wrong.

Probably not. You will see it yourself when you reach 50 years old.

I think (hope) it was sarcasm, but one sign of this time and age is, that it is increasingly hard to tell. Often people themself don't know anymore ..

So anyway, in this case I think the bitterness is real and the awareness, that it might be "just subjective" and not objective but that doesn't change the bitterness and misery of watching all those idiots out there ..