The Bay Area has always been a bit ahead of the curve there - but my point isn’t just an LGBT thing... that’s the example most relevant to me personally. People of color could probably talk about similar issues related to this kind of policy.
Of note: Basecamp was at least until recently based primarily in the Midwest, in Chicago. Bay Area culture influences them in the same way it influences all tech culture, but they are certainly situated in a different culture than that of the Bay.
(Also of note is that while SF specifically was friendlier to LGBT people historically, this is a difference of degrees: LGBT folks in SF experienced plenty of discrimination over the years. And personally, it’s the only place I’ve been called a “faggot” while walking on the sidewalk - multiple times. Anecdote, but still.)