I was involved in a UU church for a few years. It's a weird organization, and very unstable, with another revolution sweeping in new leadership (and completely new culture) every 5 to 10 years.

When I first started going, it was VERY open to atheists and secular humanists. New leadership sweeps in, and there's a mandate to focus more on "worship" and other religious jargon... and let the atheists know that while they can be fellow travelers on some of the social justice stuff, they're not really in the fold.

Last I heard, that leadership wave had themselves been swept out under controversial circumstances. But by then I was long gone.

I could never really get a straight answer on WHAT we were supposed to be "worshipping", given that UU's don't profess faith in any any particular deity or pantheistic concept, etc. I finally reached the conclusion that we were supposed to just worship the leadership's political beliefs, and not think too much or ask questions. In fairness, maybe that DOES make it a real church?