Aaand it’s already too late and you already gave all your possessions to the jerk clan leader. If you leave you’re back to square one.
You’re indeed seeing things from a clan leader’s PoV. Try seeing things from a regular player’s PoV. You want total control on every inches of the clan base - or at least be able to select who will have control. No sane player would ever join such a dictatorial structure, especially with the complete insurance he will loose everything the moment he decides to leave such a hellish structure where he can’t contribute anything, forced to bend to every whims of the clan leader.
I think you’re the one who see things completely wrong and should be educated.
Blocks, chests, etc, should have two levels of ownership. Clan, and player. When a player leaves - or is thrown out - they keep ownership of their own turf. Their thralls do not start attacking them. They don’t suddenly loose access to their own chests.
Likewise, it could be used to lock a newcomer out of pillaging or destroying other clan members’s possessions for any duration the clan leader could set. A kind of probation duration. You just join, you can use the stations, you can open doors, you can add things to chests maybe, but you can’t retrieve things, you can’t disassemble blocks or stations, you can’t, in short, grief.
Both joining and leaving should be made easier and not look like a complete submission to one clan leader, which it exactly is now.