People who need to make others feel left out are usually terrified of being left out themselves.

Deciding who is in and who is out is a way of making sure it is never you. Whoever runs that is usually not secure at all, just managing a fear by keeping the door under their own hand. Understanding it does not excuse it or make it sting less from the outside. It does mean the exclusion was never really a judgment of you.

If you are on the outside, stop auditioning for entry and spend your time where the door is open. If you are near the middle of one, notice who is being kept out and go talk to them. Nobody’s permission is required for that.