I can't make a broad generalization about all Harley riders. Of course there are some good guys.
I still wave at some Harley riders but only specific ones. And here is exactly how that demographic is split up: The HD riders wearing helmets are the good ones. The HD riders without helmets are questionable. The HD riders with ape hangers are 100% dickheads. And that's not a generalization, that's guaranteed!
I only wave at HD riders with helmets on.