I honestly believe that Robin never, ever expected to meet one of the faceless 'others' whom that legislation would effect (or someone who knows them personally, as in this case).
I suspect that it has never occurred to her before that things she says or votes for has any effect beyond herself. It is to her credit that she's clearly embarrassed by this experience. I would have lost all hope for her if she'd doubled down (like some of the people Zoe has met over the years) and said something to Joyce like: "When you grow up, you'll realise that she brought it on herself."