I should think that most of why she calls the poor woman an ice queen who hates her for no reason that she can understand is that she also doesn't understand that people around her are going to react as if she does know what's going on around her and is an active agent in shaping her future. The reason that the Evil, Anthony-Tricking, Baby-Hating Career Woman is a monster is that she looks at Liz and doesn't see what's really there. As I've said of late, the idea that what looks like a heartless manipulator whining her way into getting her parents and family to steamrolling someone she doesn't like is actually a passive dolt who doesn't realize that people are arranging her life for her to make their own lives easier would fill her with fear for what used to be a rival and ended up being a figure of pity. Despite what the Pattersons might believe, Thérèse has more than enough decency to feel sorry for someone who's so otherworldly that she doesn't know what the effects of her actions will be.
She'd also probably realize that when other members of the Patterson family complain about people who are ruining their lives, they're talking about people who also don't understand that the Pattersons as a rule have a warped idea of cause and effect. As by way of example, Mike's old boss Craig is a bad guy because he expected Michael to realize that savaging someone for trying to get him to see that his job was to do a puff piece on her would come back to bite him in the arse. It's like how Mister Gluttson is Satan himself because he wanted Mike to understand what the consequence of allowing dead wood to accumulate would have to be. As for Mira, we all know about how she's a domineering monster who wants to win all the time and enslave the Pattersons with her family politics because she expects that Mike is going to realize that his idea of doing right by his wife and children is making their lives worse.
We also have to remember that April is a spoiled, picky-faced Martian princess because she's got the inconvenient habit of trying to remind her idiot family of the real consequences of their actions. From Liz not wanting to feel bad because she doesn't want to see that rewarding a thief looks like a selfish and self-gratifying way of giving a middle finger to everyone else to her parents not wanting to see that she isn't some monster who wants lazy Mike and his family to freeze and die because she objects to being treated like unwanted furniture, she's the target of a lot of whining because stupid people don't want to admit that the world doesn't work how they think it does.