So what's the problem? What needs fixing? Well, the Timeless Isle is home to three types of character. First up, you've got the intended audience -- new level 90 characters. They're there for the catch-up gear, the easy boost to ilvl 496. There's an influx of them at the moment, thanks to the boosts. The second group is people who are there for the Celestials. They zone in, grab their kill, and leave. Then, there's the third group -- high-geared players who are there with the specific purpose of using the Censer to kill other players.
That third group is mostly targeting the first group. Entering the Celestial Court with the Censer up will get you some attention from the guards, so the Censer people are roaming the island, in search of low-geared players to kill. Some servers have it worse than others, and before you dismiss it, this problem caused the devs to hotfix the boosted 90 spawn-in to be the Shrine instead of the Timeless Isle.