It probably isn't; you don't have to worry about density altitude issues while you're over the destroyer.
And it's not just a matter of pure airmanship: you have to put the water on the right spot, or you might as well not bother. That's why they fly at such low altitudes.
It's a number of skills, and it's not the sort of thing you can pick up on a moment's notice.
Remember when we had that big fire New Years Day, after the Ramona firefighting strip had shut down? We damn near had some midairs the first day back in operation--and that was with experienced firefighting crews. 75 Seahawks with folks who've never done the mission wandering into that mess would not be pretty.
As for a few dozen buckets in the first few hours...
...don't say that too loud with the State's Rights crows within earshot. They'll loudly remind you that the Constitution never said a word about fighting forest fires, and that it's a purely state and local issue, even if the fire is threatening to burn down the naval air station (c8
Let me repeat: the Seahawk INSTRUCTOR PILOT who is my neighbor says they CAN and WOULD fly these fire suppression missions, and he can't understand why they have NOT been ordered to do so.