As others have said, these MASH guys deserve a lot of respect for what they do. Problem is that much as Roadie does not equal Lance Armstrong, Fixie-rider does not equal MASH guy (wearing spandex).
My only beef with fixie riders is with the group who totter around aimlessly at 10 mph with their aerospokes and bullhorns thinking they're the ****. All they do is block traffic and give other cyclists a bad name. I've actually had a couple yell/spit at me for wearing my team kit while out for a ride.
That being said, I really don't care what you ride as long as you ride. If you ride a pink Binachi Pista with Green/Blue Aerospokes in tight jeans and ride it like a bike instead of a fashion accessory, I'll have nothing bad to say about it.