I haven't poked my nose in Hybrid subforum in a while but I saw this thread and had some thoughts:
I rode my hybrid on group rides for 2+ years, and got nothing but compliments for doing it. Yes, the first ride I heard the question, "Who's the kid on the mountain bike?", but that went away after one ride. The only negative that ever happened is that I locked my bar ends into someone else's drop bars, which was scarey until we untangled. Others on the ride didn't even notice.
I use cycling clothes on my hybrid, and on my single speed, and on my road bike, for the same reason I wear a swim suit in the pool. Clothing designed for an activity tends to perform well at that activity.
And on waving, when I hike, I wave and say hello to everyone. On my bike, I have failed to wave to good friends riding or driving the other direction. Why? Because I am focused on the workout I am doing, and not paying attention. When I am at the gym, I don't wave to the person next to me, even if they are doing the same activity. If I am on a leisure ride, I wave to everyone.
Of course there are snobs in cycling, just like there are snobs in golf, football, and quilting. Why would that impact anyone's enjoyment of the sport?