Fact: John and Elly are burdened with the delusion that how they feel about an action is what the person intended.
The best example of this is Lizzie's good-faith mistake of breaking that damned milk bag. She didn't mean to inconvenience a pair of fragile morons but you can't tell them that. Every damned time a kid does something stupid or silly out of sheer blank-witted ineptitude, there's old Elly thinking that her children are plotting her destruction because she doesn't know how cause and effect work. She also doesn't know how memories work because of her idiotic belief that everyone who is not her or Phil is supposed to forget all the hurt feelings and constant blathering about how terrible it is to do chores and how horrible and ungrateful everyone is for also having emotional needs and how everyone is supposed to not do the stupid crap she does and so on and so forth. This leaves us stuck with Foob Fact Thirty-Five.
Fact: Since they fear condemnation more than anything else, John and Elly behave as if whatever they might be doing has no connection to how their children act when it reflects badly on them.
If Mike thinks that growing up means losing the ability to enjoy life and hating laughter and wanting to crush people who still can, it has nothing to do with Elly's short temper or John's fear of being seen as a sympathetic person with problems like they have, it's his being wicked. If Lizzie feels as if she doesn't belong, it has nothing to do with Elly's dumb advice or John getting angry at her because she feels lost and unloved. If April doesn't want anything to do with them unless it's absolutely necessary, it's not got a bit to do with being shat on by boomer assholes who resent being parents at their age. Nothing is ever their fault so they can't destroy themselves by admitting error or apologizing for idiot cruelty.