[Striiker]

He may have been camping that spot because it's safe for him while earning some plat. He could be at work and is hopping back to the game for the kills and loot only. I suspect this to be the case (or something similar). Yes, he can go elsewhere for XP and better loot but at an increase in effort and risk which he's probably not in a position to work at. I am sure that during normal play time he is off at other spots.

It's not a douche thing to do really but it does suck if someone at a level appropriate for the camp wants to do it. There are plenty of other places to go. Also, as mentioned, you could send a tell and ask him to let you know when he leaves and/or how long he'll be there for etc. He may or may not respond though so don't take it personally.

Norrath is a big place and you should seek out other camps if it's taken already.