Spoiler: It and They and generally mucking about
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They, being a flexible term, can mean "person of undetermined gender" or "group of people" or "person" or "entity" or "person of third gender" or "person without gender."

Quite versatile, really, and I find it suspect that it would be "usually" used for a particularly niche case when discussing people at the peripheries of our knowledge when that's conveniently a justification for an irrational hatred for a term.

As for IT, well, that was pretty well hashed-out the last time this came up, which was, what, 4 months ago?