You could certainly go to meetings of any of those groups. However, the point of these “atheist churches” or whatever you want to call them is that everyone there is looking for something beyond a club based around a particular activity or interest.
Joining the chess club is fine and dandy as a social outlet, but keep in mind, for those of us in the bible belt, chess club, nature hikes, craft groups, etc are apt to begin with prayer and many times have a definite religious slant to them. You can’t often escape it.
RNATB, if you’re looking for professional connections, certain occupations tend to be very well represented (at least in our group). 
… evolutionary biologists? 
I invite you to search for one of the 857 threads we’ve had on the definition of atheism. I transitioned from weak atheism (lack of belief) to strong atheism (belief in the lack) and was an atheist in both states of belief.
The Times is a terrible place if that was the purpose, because I doubt many atheists are evil types are going to read it. Their heads would have already exploded from Paul Krugman.
I was raised Conservative, and I even went to one service in the only temple we have around here, which is reform. I decided that if I could understand the prayers it was not worth going. (My Hebrew was always kind of spotty.) Anyhow, I bet half the congregants around here are atheists anyway.
Being Jewish I never had to worry about Sunday services. However we did have a Hebrew School session on Sunday morning. Probably because for a parent the best thing about Sunday school is you get nookie time without kids - wasted if you are in church.
My Sunday Holy Text is the NY Times itself.
My daughter got married in a little town in Georgia, and she got a soon to be retired judge to officiate in the garden of the B&B we took over for the wedding. He came in his robes. It was great. So, it is possible to arrange something with a JP while not giving up a ceremony.
HA! I don’t think I’ve ever heard the term “Q-tip Congregation”, though I think it likely has more to do with being in the city of Atlanta. The congregations I’m familiar with (including my own) tend to have mostly folks from 30-50, but we do have our share of older types.
That’s wonderful! My sister in Arkansas had an actual ordained Protestant minister officiate at her outdoor weeding without mentioning God or religion once. I have no idea what kind of negotiating went on behind closed doors (if any) but it was a beautiful ceremony.
Are you disagreeing with me that there may ALSO be a need for explicitly non-religious celebrants for those who want one?
Interesting RFRA-related piece on Raw Story, with some stuff related to atheists, *In 2013, Freedom From Religion Foundation head Annie Laurie Gaylor found herself arguing to the IRS that atheisism wasn’t a religion, or at the very least not a church. Even more counter-intuitively, she did this to deny herself a tax break. Gaylor had sued over housing write-offs given to ministers since 1920, an allowance brought to public attention when the government cracked down on Saddleback pastor Rick Warren for abusing his. Gaylor had sought to eliminate it under the logic that it unfairly favored religion, only to have the U.S. government counter that the housing allowance could apply to her as the head of her organization.
In that scenario Gaylor didn’t want the tax break. “We are not ministers. We are having to tell the government the obvious: We are not a church.” To everyone’s surprise, First Amendment experts sided with the government, encompassing atheists within the definition of religion—perhaps a handy precedent to have lying around now that RFRAs are all the rage.*
For most non-believers, religion-like issues are simply not much of a concern. To me, the religious people just look like a bunch of self-flagellators – I have enough problems as it is; beating myself up over them seems, well, redundant.
Your community has active cooking clubs, chess clubs, and golfer’s clubs? We certainly don’t, and as missred pointed out, if we did, they would be full of Christians. Frankly, I feel surrounded by them most of the time.
In any case, Sunday Assembly gives me more than a group centered around a hobby. In any given month, I can go to the Sunday morning assembly (held only once a month, btw) where I get to listen to live music, hear a talk, and then join others for lunch, do a service project (cooking at a homeless shelter, for example), socialize at a potluck brunch, discuss a book we are reading, and learn a little about home gardening from a fellow member who is a avid gardener. Even better, all of this is geared to being able to socialize and build relationships with people who are probably more similar to me than anyone else I am likely to meet. That’s the point so many of you are missing: atheists/agnostics/non-believers are likely to have lots in common with one another (e.g., being liberal, valuing education and the arts, interest in science) and most of those things are uncommon where we live.
If nothing else, non-believers of the various stripes can always sit around and swap war stories about how we deal with religious debates and proselytizing by believers. We always have at least that much in common. 
Brynda: Thanks, BTW, for participating. Good to hear about SA from a current member.
Thanks! Just doing my part to fight ignorance!