The best venues I found are coffeshop/bars where primarily local people gather, with a smattering of interesting people from out of town, with an atmosphere that encourages free speech and inquiry. Enough of a public house to be inclusive but the trolls are well-moderated. There is a level of decorum, granted, a low bar in places I frequent, that people must maintain or you get kicked out.

Unfortunately there seem to be less places like this now.