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”.
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.