What makes someone a "bad" religious person? In my opinion it's irrationality. The anger, hatred, bigotry and oppression that religions often exhibit grow from this, from believing that men can speak for God(s.) Without any sort of rational basis and with ever-changing divine mouthpieces, it's just a matter of time before, "God wants you to love thy neighbor," becomes, "God wants you to kill the heathens."
But they go to church because ultimately life is hard. And boring. And lonely.
The universe is incredible and mysterious! There's always more to learn and discover. If it seems boring that just tells me that one needs more experience and stimulation, to learn about human knowledge and its limits, to explore different environments and cultures, to do something other than provincially sitting at home steeped in ignorance, tithing and being pious.
Life becomes less hard when we band together and make this one life we get as good as we can for everyone, systemically, rather than living it as though it were just a prelude for something better. It becomes harder when we leave the social safety net to religious organizations who offer it with strings attached and gaps in coverage.
And average people just feel the need to have a sense of community. It doesn’t matter where that place is, but people are social animals and need a certain level of human interaction once in a while. A community church gives them that.
So does Kiwanis, Rotary, Elks, Toastmasters, Masons, etc., There are many social organizations that are more secular. There's tons of events online at any decently sized population center. Churches don't have a monopoly on social gatherings.
It gives them a place to get married. And to hold funerals in. There might be a local strawberry festival at the church where they see their aunt Mary or at service every few weeks where they see that cute girl they have been trying to build up the nerve to talk to. People don’t have a ton of those opportunities elsewhere. They really don’t.
Banquet halls, funeral parlors, and festivals can all be secular! You can run into relatives and cute girls in many venues that don't require professing irrationality. I suppose it depends on where one lives but in a big city I could probably attend a street festival type event every day of the week, not sponsored by churches.
Once you are out of college, the number of friends you have drops dramatically and the opportunities to make new ones drops even more. You aren’t typically going to be going out to the bars every week past your 30s and asking someone out at a grocery story is creepy. Worse yet is trying to make friends or find partners at work. Your ability to actually socialize is incredibly limited after a certain age and church is a very easy way to do that.
Not necessarily, but after college it is up to the individual to put in the energy to meet people, it won't happen as automatically just going about your life.
There's nothing wrong with asking someone out at a grocery store as long as the interaction is wanted and you aren't harassing them.
I agree that socializing at work can be a bad idea depending on where.
What about dating apps? Events and festivals?
I agree with your thesis that churches provide a lot of these services, especially in small towns, but that does not mean there are not viable alternatives that already exist. I'm certain we could craft vibrant social lives for ourselves without having to play pretend.