My son lifeguards at the local Y for his part time job. The Y here is considered to be a great place to work (although it would be wonderful if they paid a bit better). The YMCA here promotes "people getting along with each other".
I asked my son if religion is ever an issue at the Y. He says the corporate philosophy is a "be good to one another", as the Y here is very involved in social programs and helping children and the poor. So the only mention of anything to do with religion, and even that would be stretching it, would be to say they promote "The Golden Rule", which they do in a philosophical sense, not by anything to do with Christianity.
Of the 4 guards on duty last night, 2 were Jewish, one sort of Anglican, and one Catholic. They all worked well together and like each other.
I personally know of members and staff who are Moslem, Christian, Jewish, Buddist, athiest/agnostic, and many others who could care less about religion.
The Y welcomes Jehovah's Witnesses, just as they welcome anyone else. As a non-JW, I have to say, this WT policy is so wacky, like so many others. I do believe this policy is enforced here, from how my daughter's ex-bf wiggled and squirmed to make sure he never had to set foot in the Y.
On a thread about this same topic a while ago, a poster from the Southern US (I think) mentioned that they Ys there are more "Christian", but here, they definately, deliberately downplay religion in order to make everyone feel comfortable and welcome.