I don't think most lefty-left Westerners are also pro-China. I know in my circles going after China—however ineptly and weakly—is probably the only major thing Trump's done that any of us agree with.
You do realize that Y Combinator the business is a separate entity from the thoughts and views of the thousands of people who comment here, right?
pg and dang aren't sitting here in the comments slapping everyone for posting their political ideologies. There certainly is not a small number of commenters with a negative view of capitalism here.
Just search for phrases like "late stage capitalism" and you'll find them.