I think that's the whole point though. The article is saying that there is too much heat simply because they express their opposing viewpoints. "Stay out of the kitchen" means "close your mouth around Silicon Valley liberals" or you'll experience backlash.

While this may not be your personal experience, the article essentially says that the somewhat ironic message coming out of the Valley from people in the "party of tolerance" is that they tolerate everyone except those that have opposing viewpoints.