... i dunno OP, the guy who wrote that letter had a point: the sugar-coating of awful things HAS blown up in our faces, and there really IS a pernicious romanticized fever dream of fascism being tolerable right now. We need to confront the shit happening and teach the youth that the shit is, in fact, shitty.
I don't think that was the case in 1981, though I wasn't alive and can't say it for myself.
Also, the trolls, as far as shown in the comics up to the point the reader mentioned, weren't fascists. Isolationists, greedy, cheating, cowards and distrusting of non-trolls (aka xenophobes). Calling them fascists from that is one hell of a leap, no wonder the author snapped at that with "look it up on a dictionary".
Elfquest is the best comic book series ever written. The Pinis are treasures. Awoooooh!