A few roadies will not wave even in the middle of nowhere. Usually they're the very "serious" looking ones themselves, they often have beards, always dark shades, and always have an expression like they're not really enjoying themselves, and theyre often riding an 8 grand bike. Ah, who cares. Leave them to their Strava segments.
There's some truth in what you say, If I ride my tourer in my cycling clothing, I get waved at a fair amount out on the open road, especially in remote areas. If I ride my hybrid in my pub clothes in my town however, I get zero waves, but it's not a disrespect thing, it's just what happens. It really doesn't matter. Ride your hybrid and enjoy it.