Historically, secular fraternities like the Freemasons played a big role in keeping mixed-denomination communities communal, instead of fracturing off into hard, non-fluid segments. I would conjecture that we owe a lot of our cultural religious tolerance to the foundations of trust and community laid in the Masonic lodges of yore.
IMO it's a shame that these groups are not very widely established anymore (at least among "younger" people, who are now becoming "older" people). These fraternities do a great deal to help adults, families, and whole communities.
The only reason I haven't personally seriously inquired into joining such a group is that I'm already in a very active church community that covers most of the Masonic functions, and I have enough trouble just keeping up with that. I'd miss too many lodge meetings, etc.
For anyone who is floating or looking for a consistent community to anchor against, that will be there as an instant community even if you move around, Freemasonry or similar orgs are really worth investigating.
I guess people in the past had more free time to spend on non-work activities like this.
It means that a freemason have to hold contradictory positions as true. One might be an atheist by one cannot reject the so-called supreme being, one might belong to an Abrahamic religion but one cannot reject the Hindu pantheon. And within the Abrahamic religions it's more contentious than anything.
It's an expression of the Orwellian "2 + 2 = 5", and it's a very dangerous anti-realist totalitarian ideology, and it should be rejected whether you're a theist or an atheist.
In ceremony/ritual we refer generally to "The Grand Architect of the Universe", instead of any specific diety.
BTW, Freemasonry is NOT intended to be a religion nor a replacement for one, and we don't want to be. We just use symbols and allegory that relate to the story of the building of King Solomon's Temple.
Seems too broad to really be helpful in this discussion. The park in Chinatown where people gather to play xiangqi is a "third place" but nothing like a church or Masonic lodge.