Uh, that ball bounces both ways. Here are the guys I've flown with/seen that have been mostly prominently sporting DPA stickers and lanyards:

...a long-time ALPA non-member; he has always been a non-member in good times and bad; methinks he is just trying to skip out on a large payment of past dues

...a fat, slovenly dude in the concourse walking with hat in hand, jacket unbuttoned, and clip-on tie clipped to his epaulet! Nice professionalism there.

...a fat dude who regaled me with the most disgusting jokes and of his fondness for appalling porn that I have ever had to contemplate in my life. Don't get me wrong: I like "underboob" as much as anyone, and I've told and enjoyed listening to my share of racy jokes. But "racy" is to this guys' fetishes as a kid's homemade go-kart is to an Indy car.

I am sure there are a lot of great DPA guys out there who truly believe that alternate representation is in our collective best interests, and can state their positions eloquently (without insults) and are the kind of guys I would be happy to drink some brews with. Unfortunately, I haven't met them yet, and those I have met are they themselves the strongest arguments against the DPA.