I think it's stupid to make business decisions based on just that (of course, the content of the speech matters - e.g. if you are a coal miner and the speaker says she will bankrupt coal miners, it's prudent for you to exercise extreme caution in dealing with such person). But that's not where we are at. We are at people trying to shame YC into making business decisions they obviously don't want to make based on shaming mob's political preferences.
One qualifier would be giving a full speech at either the democrat or republican convention. That's intentionally putting yourself into the political system, and it's okay if people make business decisions based on it.