Open Letter to Paul Graham about Peter Thiel

PG and Sam Altman aligned and organized against Trump who has as a supporter Peter Thiel. Now, because of the election outcome, the writer is asking that PG take the step of distancing Y-Combinator from Peter Thiel.

Peter Thiel is an investor in YC. Surely, he has rights and cannot be penalized wrt the company for his political views. What am I missing here?