Particularly in immigrant and black communities (and conceivably in Central American/hispanic ones as well), the church is the focal point of civil life. It is a resource not only for instrumental support like counselling and a financial safety net, but as an existential anchor. The prospect for many of “leaving the church” is not so simple as just getting to sleep in on Sundays -– it has real repercussions. Setting up a humanist church speaks directly to those people: “you don’t have to ‘leave the church’, you are simply invited to switch churches. This one doesn’t have a god in it”.
To reiterate, no one is making you participate in this stuff if you don’t want to. There are plenty of ways to build community and this is simply one option (albeit one that may be growing in popularity). The amount of pushback against people who want communities like this is astonishing, though. It’s as if taking any aspect of the church experience — a title they use (“chaplain”), the times they meet (Sunday mornings), the things they celebrate (rites of passage), the ways they connect with like-minded people (small groups) — somehow justifies religious belief.
Churches don’t own community-building and local leaders any more than they own marriage. Might as well find a way to use the best practices in a secular way while getting rid of the bullshit that usually comes attached to it.