Someone who finds a hunt mark with their party first and pulls it- not a troll.
Someone who doesn't find a hunt mark, and is simply near the front of the line of people to get there immediately after it's announced (and before the person who found its party can even arrive) and who pulls it- definitely a troll.

Some do it over and over while there's a couple dozen people behind them who perhaps might not have the same VOIP client or unauthorized plug-in to help them get there as fast. People in the game can dick each other over without breaking the ToS, and that's what Naming and Shaming is meant to be used for. I don't do hunts anymore because I find the content disappointing- it could have been challenging and fun, more like Odin/Behemoth or the 30 min 'ooh this is too hard for most people to bother with' fates and less like 100 people in a tightly packed room trying to stomp on an ant and get credit for it. But I do like seeing other people do it.