This seems reasonable - becoming a key member of a political campaign means signing on for that sort of thing - but I'm struggling to reconcile it with the earlier statement. If making Trump supporters uncomfortable about entering a business arrangement is a good thing, surely that's about trying to put economic pressure on Trump supporters in general?

I'm not trying to be uncharitable here - I honestly don't follow. One possibility is that since YC founders often end up quite wealthy, you're talking about discouraging the next Thiel rather than discouraging business with Trump supporters in general?