I wouldn't say "brooding," but I was once told by Stu Fields, the publisher of the now-defunct Experimental Helo magazine, that "helicopter pilots are not joiners." There are no big clubs for helicopter pilots, in part because there's no significant recreational helicopter market. It's so expensive to fly them that only a few rich guys do it for fun. Most are on the clock, and in many cases their employers belong to HAI, but they don't join as individuals.
Utah Rotorcraft Association is a 501(c)(3) dedicated to education and training for experimental rotor-wingers in the intermountain west. Lots of gyroplane guys seek us out, but when we hold our regional meet, we can't get a guy based at our airport to even roll his experimental Helicycle out of the hangar to be seen during the Young Eagles rally.
So, "brooding," no, but "loners," in my experience, yes, at least as far as interacting with the rest of aviation.
Two other possibilities have occurred to me:
(1) They're too busy fighting off girls to spend time with us.
(2) Any aircraft with fewer than 1,150 moving parts bores them.