After witnessing his minor meltdown on Twitter the other day I thought to myself celebrities will really need to learn to ignore the trolls. I'm sure Trent will be just the first of many Twitter celebrities to go through this.
It stops being fun for them and it comes down to business. If they are not getting enough out of it to put up with the crap, they will stop or pawn it off on PR people to do it for them.
Same reason Obama and the likes don't watch cable news.