Are they a net good or bad? Do/Would you donate or volunteer to one?
I don't see them as being different than any other charity or organization trying to raise money for their cause. That said, some charities are decidedly bad news regarding their handling of funds. Before giving to any group , one needs to check them out carefully, and see where the money REALLY goes !
Having grown up inside a church structure I was privy to the planning and attitudes around the various charities, and the main aim was tom proselytise.
I would very much prefer to give to a secular charity, such as Foundation Beyond Belief. I think we’ve reached a point where we no longer need to give to or volunteer with religious charities at all, so I won’t even qualify with, “if there were no other option.”
I think it depends what their mission is and also what they actually do. Specifically, I would be opposed to one if they push their beliefs in the process of carrying out their mission, and avoid one even if they don't. If I felt like donating or volunteering, I would rather find non-religious organizations of similar mission (or one that matched -my- objectives).