Blacklist for housing when?

[Jojoya]

Every other MMO has a system like this, why can't FF14?

Blacklists are generally client side, not server side, which is why they're limited in what they accomplish.

The other MMOs with housing that I've played didn't have a housing blacklist. Instead they had a housing friends list so you could select who could enter if you didn't want your housing open to all players.

The more you react to this player, the more you encourage them to keep behaving as they are. And I find it unusual that you know so much about this player you can claim they have other accounts that have been banned.

All you can do is support tickets for harassment to the GMs complaining about this player's behavior and discussing how it's making you along with others in your FC uncomfortable, disrupting your game play.