While Jamal's point is certainly arrogant, there *is* some merit to it. An okay-ish cannon would get comparable, if not better, exp/hr (with less risky mob spawns/mob specials) on Greater Colibris. A more balanced party shouldn't be in melee cannon spots at all, and should instead go SC + MB on trolls (where the free bonuses to damage are useful, but plain old melee DoT, while it works, doesn't shine as much due to trolls' high defense). And so on.
While it's not really reasonable to say "get out of this camp because I can make better use of it than you can", it's very reasonable to say "free up this camp for someone else as a side effect of going to a camp that's better suited for you anyway". The quality, jobs, and overall makeup of the party determine which particular merit camp you should go to.
I don't look down on people taking up a good spot for them, even if it's a better spot for me. Shit happens, they got there first, life is hard for me. If my party really blows them out of the water, it's easy enough to outpull them until they give up anyway. And if not, then it's my responsibility to move because I *wasn't* there first. But I'm sure as hell gonna look down on them (for their stupidity/ignorance about picking out an appropriate camp) if it's not even a good spot for them, and they're still taking it up.
(Tangential note: if there's another party at a camp you want, and they're killing everything anyway, and thus you *don't* blow them out of the water ... don't gimp both parties' exp trying that outpull-till-they-leave method. It only ever works if the first party there is pretty damn bad, or if they were gonna end soon anyway. Otherwise it's just a mark of your own stupidity that you'd rather go for uber-competed - and thus painfully slow - exp instead of move somewhere else.)
Back to the point, the fact of the matter is that mobs which are prime targets for elite cannons are often not the best choice *in the first place* for non-elite cannons or non-cannons. So whether you care about the elite cannon that wants your spot or not, why subject your party to a camp when you *yourself* could do better elsewhere?
EDIT: Case in point:
Your blanket statement is false. Try again with more understanding of what party setups are suited to what mobs.