If I were to start something up, it would start with a clubhouse and probably two employees—one is an event organizer who plans parties and other special gatherings, and the second would be a host/hostess that is responsible for welcoming new members and ensuring they’re comfortable as they try to fit in. Maybe something like an “onboarding partner” would work too when you’re trying to scale.
I think in-person power dynamics are often not immediately obvious, and "inclusive" groups sometimes make it worse.
For example, cases where the inclusion of someone who's socially awkward lead to the self-exclusion of some other people.
Someone's social awkwardness could lead them to constantly stare at people they find attractive; the leaders or organisers of the group might be too nice to exclude said person, since they didn't do anything criminal like harass people, just awkwardly stare at them; and other people might choose to self-exclude themselves because of this.
It’s generally funded by synagogues and charity foundations.
I’d of thought the Christian churches/denominations have similar programs.
It could be unique to Jews due to historical and present anti-Semitism. E.g. Jews were (and still are in a few establishments) barred from many fraternities, country clubs, athletic clubs, summer camps...etc