This isn't nearly as true anymore. Most clubs are all rank and as stated civilans are allowed so enlisted can't really be rejected.
Are you telling me that nowadays active duty E1 - E3, E4 - E6, E7 - E9, O1 - 03, 04 - O6, and O7+ all rub shoulders at the same club?
I am aware that at most .mil facilities retired military of any rank are allowed to join the local O-club, although retired enlisted are sometimes encouraged to join the Senior Staff/Staff Enlisted Club instead. But any former .mil (not retired) joining the local O-club? Don't recall ever running into that. And civillian employees assigned to the base were permitted to join the O-Club - often explained
as because they outranked even the Commanding Officer of the base.
Of course, it has been at least 20 years since I was on a military base other than to transit across to the other side via the public highway. Back in pre-history the social segregation of the ranks was strictly enforced - including romantic/platonic liaisons.
stay safe.