Waving is a gift you give, who cares who waves back.
Wonderful sentiment Wombattle!
I find that most HD riders acknowledge you if you wave to them up here, usually a lift of the head or a lift of a finger off the throttle. I often get waves from 1%ers too, if they're riding on their own.
But who cares if they don't wave back, I've waved to them, that's the important thing. You never know, it might be a newbie and it's the first wave they've been given. Now that is a gift!