As someone who is atheist I am also engaged in lots of community activities and groups. None of those groups are based on being atheist. If they were that would be like joining a group founded on the premise that none of us collect stamps. That would be odd.
A religious community is one of many. Religion didn't invent community, rather community invented religion. As to the OP, sure, community is important to people. What distinguishes religious communities, generally speaking, is that its members share a belief in a specific woo or at least pretend that they do.
I see it a bit differently than you do, when it comes to atheist groups. We are old now and traveling for an hour or more to Atlanta has become too much of a stressful chore, so we no longer visit the Atlanta Freethought Society meetings. But, when we did, we always had a wonderful time and some of the speakers were fantastic. My favorite one is the guy who wrote the book "Atheism for Dummies", which I've read twice. There was also a history professor who loved to speak to our group, probably because we were more interested in what he was talking about, compared to most of his young students. We had a geologist give a detailed speech with charts on climate change. We had a Muslim speaker manyl years ago who made the case that most Muslims in the US are liberal and have no desire to harm anyone. That was a few years after 911. We also had a Mormon speaker once who told us about her time in prison for embezzlement and how she was now trying to live a moral life etc. So, the speakers come from a variety of backgrounds and are usually interesting. I doubt any mainstream church would allow an atheist to speak to them.
So, getting together this way allows one the opportunity to meet a lot of wonderful people. I do agree that we don't do a good job of supporting each other, like most churches do. For example, a poor Black friend of mine needed some expensive dental work. I offered to help pay for it, but she told me her church is helping pay for it, in return for her doing a little bit of work for the church. Atheist groups aren't known for that type of charity, but then, we haven't been organized for centuries like Christian groups have. I don't know what my dear friend would do without her church community. She is one of the most loving people I've ever known. She's not highly educated and has always had health problems. I do wonder if she would be so happy without the support of her church community.
Most of us were fairly liberal when it came to our political views, so we did have a lot of things in common. Plus it was fun meeting a variety of people from different backgrounds who for one reason or another had become atheists. The last meeting we attended was presented by the "Black Nonbelievers of Atlanta", a group that is made up of mostly females. The speaker was very interesting and I had a good time joking with them about being the token white woman when I asked if I could be included in a photo of the group. I miss those good times. The pandemic caused the meetings to be stopped for over a year. They are going on again, but I'm not sure we will be motivated to drive that far again. That's another problem. Most of the members of the groups in large cities like ATL, don't live very close to each other.
I would probably join a UU Fellowship if there was one in my area, but the three that I know about are over an hour's drive from us, so all we have is our small group that tries to get together for dinner once a month. I've made friends with a couple of the members and we always enjoy getting together. The conversations are non stop and we usually end the evening with hugs. It's also nice to know that there are others in the area who don't believe in gods, although anyone is welcome to join our group. One man who comes when he has the time, was raised in an evangelical home, he is also gay and is currently having some martial issues. His husband has moved to the other side of the country. We at least try to give him a little emotional support. He's not quite an atheist, as he's still investigating different religions, but he told us at our last meeting that atheists were the most fun to be around. Perhaps if you had much experience with our free thought groups, you would understand why we like them so much. The AFS has been around since at least the 80s, so apparently some people do find the group an important part of their social life.
IIDB is an atheist group imo, and I feel as if I know many of you, even if we've never met in person. It's just more fun and personal to get together in real life. It's also easier to have conversations without misunderstandings. I have fond memories of many of the older folks who have died over the years, as we began visiting the AFS about 20 years ago. One of my favorites was a man in his mid 90s who was still very sharp and loved telling us about the most recent book he read. It's not that we celebrated atheism, it was just a nice break to be around a fairly large group of nonbelievers, especially for those of us who live in the Bible Belt.
I didn't mean to be so wordy, I'm just trying to give you a taste of why atheist/freethought groups can be interesting and a lot of fun. Your social life may be so full that you don't feel the need for this, but a lot of us do value our atheist social groups.
