I get waved at by everyone, and I wave back or initiate with anyone. If they don't wave back, it's prolly because they are new, novice, or plan on doing something with the clutch.
People waved at me when I was starting, and I was too nervous to respond.
But the blessing of the bikes I went to last week had a nice speech from the reverend. She said that "I noticed bikers wave at each other, regardless of what they ride. I think that's absolutely stunning - because it's a moment when you can pause and understand a fellow human being who, like you, takes risks to fully enjoy life. You're acknowledging the fact that we all deal with hazards, and try our best to make it home after every ride"
And it holds true. IT's not about status, it's not about brands. It's not about styles. And it's not about knowing someone.
It's about being on the same boat for the same reasons.