From the perspective of a former CC-only guy (who now OCs sometimes), I associated OC with the people on youtube who purposely get officers to notice them, because they like attention, like this guy...
http://www.youtube.com/watch?v=hBWghJrVeYA&feature=youtu.be
I think that once I looked more into open carry, and realized that most open carriers just want to exercise their rights, without getting attention, I became a supporter and an OCer (sometimes).
CCers are afraid (as I used to be) that OCers are going to garner too much negative attention, and get OC and CC banned, and damage the 2A cause.
I think, as with all things, educating CCers about the use of rights, and to not accept the pressure from the anti-2A crowd to cave by concealing, then OC will be much more accepted. However, on the other hand (and rushcreek, this is not directed at you or anyone else in the forum, because your frustration with CCers is, in my opinion, merited to some extent), insulting CCers and being "in their face" is not going to help.
I was converted to seeing the benefits of OC by reasonable and friendly OC discussions with OCers. Now, I am an advocate of OC as well as CC. As the old cliche goes, you catch more flies with honey than with vinegar.