You're assuming the butt of the joke was just the pilots. While growing up I heard jokes about "Pollacks" with the last names deliberately mangled for humor. (I have an uncle who is of Polish descent; my own last name is Romanian.) The jokes might have been triggered by some individual's mistake worthy of derision, but since I sometimes knew the people making the jokes I knew they weren't thinking of insulting just that individual. Their target was the whole group.
So forgive some of us for being skeptical about the intended target.
Anyway, since it shouldn't be that difficult to make humor without being a bone-head, why do it? And why do the equivalent of an Internet high-five over this prank?
Anyway, the count is now 3 dead. Unknown number who are likely to have injuries for the rest of their lives.