I think a better way to view these types of groups (and why they are so specialized) may be to view them as support groups almost entirely focused on pragmatic

I think a better way to view these types of groups (and why they are so specialized) may be to view them as support groups almost entirely focused on pragmatic results and functional improvements (as opposed to psychological ones). Restricting them by defining characteristics encourages people defined by those same characteristics to participate when otherwise they might not.