What year did Harley guy stop waving at other bikers?

I started riding street bikes in 76 and everyone pretty much did the wave at everyone. Didn't ride street bikes between like 96 and 2002 and when I came back I noticed most Harley guys only do the wave to other Harley guys. I have a sport bike, a European dual sport and a barely street legal dirt bike and no matter what I'm riding, everyone waves except Harley guy. When did this start?