I've looked into all of these orgs and every single one of them requires the belief in a "God". That has to be a huge turn off to a lot of younger people who might have been interested in joining for the social parts of the group. All of them lost any interest from me because I'm not going to take an initiation oath claiming to believe in a God that I don't believe in.

If they really want new members, they need to self-reflect on antiquated requirements that might turn off younger people from joining their organization.