Unfortunately the trouble with stereotyping is that good folks get caught up in it and in many cases you can't tell who is a "good" biker from one your disdain based on the 3 sec encounter you have with them. Since I ride virtually every type of bike made I get to experience all sorts of this nonsense. People who are nice to me on my touring bike give me attitude if I am on my fixed gear. People who think my cargo bike is goofy think I'm cool on a road bike - or the other way around.
It never ceases to amaze me how a small community like cycling is always looking for ways to subdivide and criticize other cyclists. I'm just happy I see someone else on a bike!
I still need a unicycle to complete my collection... like you I am always happy to see anyone on a bike regardless of who they are.