The thing you have to remember about this woman and those like her is that she genuinely doesn’t know that anyone disagrees with her basic worldview. She doesn’t even see it as a worldview. It’s just the obvious truth.
Of course she knows abstractly that half the country voted for Trump. But those aren’t people. Those are cartoon characters. They’re either fat slobbering rednecks in klan hoods, or mustache-twirling robber barons manipulating the rednecks for profit. Her mental models of them are less complex than her mental model of a squirrel. Anyone she might actually sit down and talk to is, of course, a person, and therefore agrees with The Obvious Truth. It is inconceivable to her that anyone capable of being a pleasant dinner party guest would not share her basic beliefs and values.
She wasn’t trying to do a gotcha or extract a pledge of fealty. She was certain that Sydney Sweeney is a person, and therefore only got mixed up in the whole jeans/genes fiasco by mistake. She was trying to do Sydney a favor by giving her a chance to clarify that she is in fact a human being who agrees with the things all real people agree with.