Yes it is, as all your supporters have pointed out. I know you didn't outright say it yourself, but there is nothing else at issue here. This change only positively impacts legitimate, non-camping players because now they have a high (if they fight the boss with one other person) or guaranteed (if they get him alone) chance to get the main loot drops.
This is all about people wanting to camp and upset that their easy mode, selfish path to loot has been throttled back a bit - not stopped, just slowed down.
Sooty , camping/farming has been around in mmos since the very beginning , so no it is not easy exploit or anything like that , not that you would apparently know what an exploit is apparently........secondly , this loot is locked out GLOBALLY........
Although I dislike the camping/farming thing myself and only do it when absolutely necessary (like collecting a few soulshards for a dungeon run or whatever), you can not fairly argue it is 'easier'.
This is a GAME. The only easy vs. hard measurement you can apply is TIME. And, I can assure you, you do not make (as a normal player) make more in game wealth with your time spent farming pub dungeon bosses compared to other means. It's simply a means to use the time in a different way and still have some reward for that time.
If you really wanted to get rich, you would use hirelings and alts. Simple as that.