SE has no reason to do anything about it because they're not doing anything other than standing there. If SE took action against them, they'd have to take action against all other players that hang around the Limsa Aetheryte.
You've got the ability to not let it annoy you by ignoring them (what I do if I end up visiting whatever world they're on for the day), taking alternate routes into/through Limsa, or not going to Limsa unless it's absolutely necessary. There are vendors, marketboards and Summoning Bells in other cities. If your GC is Maelstrom, it's not hard to get First Lieutenant so you can buy the Maelstrom Aetheryte tickets and avoid Lower Deck completely.
Agreed. It's impossible to get rid of large standing rocks that have no brains to reason with when they're not doing anything wrong. (not saying you as the individual player have no brain, just that your AFK characters don't have one).