What happened going in is that Paul had made the rather foolish decision to describe Lizardbreath to his folks. This was, at best, a questionable idea because the doughy ninny always seems to derive the wrong lessons from what people tell her. Let us remind ourselves of the fact that she combines a horror of not being included in a group with a distinct disinclination towards doing difficult things should those things be a requisite and a tendency to regard those who ask the impossible of her as hating her. Let us also remind ourselves of the fact that she hasn't a clue as to how people see her or why people do what they do. Adding these phenomena together reminds us that Liz, having remembered Ugly Brother whine piteously about how his mother-in-law hates him for no reason and how that awful woman who made those awful accusations hates her for no reason immediately came to the conclusion that his family would hate her for no reason. It probably is never going to occur to her that her flighty nature probably gave them the same reason to not care about her feelings that she gave Paul, Susan or the good people of Mtigwaki.
This is because she seems to me to represent the part of Lynn's mind that never quite managed to admit that people do not actually perceive the world exactly the way she does. Liz probably told herself that it was for the best that she never did meet them because since she knew that since meeting in-laws worked out so badly for Michael, they should be grateful that she generously spared them having to go through something unpleasant. She also told herself that Warren was just being generous because since she didn't suspect that he had an ulterior motive, he obviously didn't have one despite his actually God-damned telling her he did. It's akin to how THAT WOMAN is just being difficult because despite what she says about her fears of being humiliated by some manipulative blond playing dumb, she knows that Liz isn't trying to rub her nose in the fact that everyone wanted her to marry Anthony. Being told to her face that people are willing to move Heaven and Earth to make that happen also doesn't make a dent because she assumed that her passivity was their passivity. What's really amusing about all of this is that the same person who can't understand how people feel whined pathetically that about no one understood how she felt at all.