Fair, but I'll mention that I'm in one of the most liberal states in America and it's not as big in my department. I routinely see professors and my advisor say stuff that is far from PC. Though I have heard of a junior professor say that we shouldn't refer to orphan processes because it might offend orphans. Kinda wish I was there, because as someone who is orphaned (single parent, not both) I particularly feel offended that he would think we're so weak that we'd need to be coddled.
Our union doesn't give the STEM departments much respect. They seem to particularly hate CS and the Economists...
Admittedly my sample size is small, but it gives evidence that we shouldn't aggregate beliefs about people. I'll admit, I'm frequently frustrated when people hear I'm in grad school that they immediately think I want to lick Stalin's boot. Such an interaction happened just yesterday on here where a user called me a communist when I was calling meritocracy a fool's errand. They didn't see the irony and somehow those comments got removed. Rare occurrence here...
CS and Economics are the departments least influenced by left wing ideology from what I've gathered. I assume Math and Physics are similar in that respect.
The sample size of the people I've interacted with is admittedly very small.