I agree with you, up until the point where you are a public figure. That's a grey area but once you're a public figure, which Thiel was after (if not before) his RNC speech, you should be judged on your actions and speech whether or not it was related to your role at an organization. It's like newsworthiness. It's grey, but we let the media decide what is newsworthy and what isn't and we let the market decide if they're right. A lot of things the Enquirer publishes aren't newsworthy, by common standard, until the public buys enough of their tabloids to prove us wrong.

A public figure == https://en.wikipedia.org/wiki/Public_figure