[yummyfajitas]

STEM (by which I'm guessing you simply mean computers) is suffering the exact entry by MOPs and sociopaths that the article describes. In addition to the hardcore geeks we used to have, we now have a lot of lightweight techies who aren't deeply interested, and a lot of non-techies calling themselves techies because it seems cool (e.g., "growth hackers").

We used to have Paul Graham and Alexis Ohanian, now we have Sam Altman and Ellen Pao - pretty definitively sociopaths by the definition of the article.

NRX (which explicitly rejects libertarianism, BTW) is a good example of putting up barriers to entry. My political views are significantly influenced by them (their critiques of democracy are spot on), but I'd be pretty explicitly denounced if I were to sufficiently publicly call myself one.