While all or most sport bike riders would usually wave to me the Harley crowd would not while I just waved at all bike riders, not because of the brand of bike they had but because we obviously shared the open road. There are some cruiser guys that give me the wave and I do the same, again because we share a common interest/passion/vision, whatever you want to call it. I think it's pretty sad when I ride mi bike and Harley guys are just too cool to wave back. I almost laugh at how tough they try to seem with their scouring facial expressions. But then I noticed on some of my longer rides that some Harley guys don't even acknowledge their own kind.
It sounds like you have a little attitude against H-Ds. Maybe you just don't see us wave since you're usually blowing by at 130 m.p.h. I'll admit, I don't wave unless somebody waves at me first. No big deal. If I wanted to wave, I'd join a parade. As far as the "scouring facial expressions," I think it is a from watching a person ride a motorcycle ( or should I say "sport bike') looking like a monkey humping a coconut. Driving the vette I always wave at another one, even if they don't. It's a vette tradition.