I'm sure you're following these threads. They're filled with xenophobia. For example, in an article covering similar material currently on the front page, the top comment calls H1Bs "scabs", and it is unquestioned. Contrast this with when someone criticizes some feminist policy on these boards; they're called out pretty quickly. Being thought of as "sexist" is taboo in SV; being a "xenophobe" is just patriotic.
This is just one of many "communities" I frequent. HN is very self-righteous about the level of conversation and discourse here. For the most part, it's pretty good. But introduce the right topic, and you'll quickly realize that the people here can stoop pretty low.
Your claim about SV is also far from true, in my observation; the opposite is much closer to true. Generalizations about HN and SV often go hand in hand, and that's another fallacy: they're two worlds that overlap less than you'd think, and also conflict.
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Edit: a later name for this Maxwell's Demon analogy is the 'notice-dislike' bias: https://hn.algolia.com/?dateRange=all&page=0&prefix=true&sor...
More on 'demons' here: https://hn.algolia.com/?dateRange=all&page=0&prefix=false&so...
People are people. Xenophobia just happens to be the discrimination that this community accepts.