I'd like to know what you all think as to why it started in the first place.
I started riding in the late 60's. I don't remember it being a thing then.
I think the wave thing started with the HD riders. To show brotherhood and a kindred spirit. That's why "other" riders aren't really included. Don't matter to me. I don't wave. Like was said above , do you wave in your car? Of course not. I'm not unfriendly. Just prefer to keep both hands on the bars. If I'm riding local and see a rider I know then I most certainly wave. Maybe even blow the horn.