what exactly constitutes a troll?

sorry for the naive question, but what is all this fuss
about Mxsmanic? may be am I missing something obvious,
I must confess that I haven't read all his posts, but I
am a bit surprised by the rather hostile reactions that
he received; I mean, ok, he doesn't fly 'for real',
and sometimes his questions are a tad naives, but hey,
as far as I am concerned if he is an aviation enthusiast,
or at least a wanna-be, I don't see why he should be
shuned. May be he cannot afford to fly, may be is he
too young, may be is he a dog -- this is internet
remember :-) -- or whatever, but we seem to be getting
along just fine with Skylune who advocates grounding
us all, so what am I missing?

--Sylvain