https://ineedcoffee.com/the-coffee-house-a-history/
They rapidly became a place where people from all walks of life could, and did, come for lively discussion. And their rapid increase in popularity caused them to collapse from their own success.
Early access to the internet was, by definition, limited to people who were on academic or military networks. But by the time BBS culture came about, it was the thrill of finding like-minded folks from wherever they might be- it was not a culture based on exclusion per se, like what you would find at a country club.