I never completely understood the concealed nazi's point of view, legal issues not withstanding of course...
In some places OC is legal. In some places it may even make sense. Generally though it has a significant potential to scare the general populace and expose the packer to added hassle and danger that would not be there otherwise.
If made it is easy enough for someone to make a claim you threatened them, true or not, and the presence of the gun will automatically put you on the defensive. You are also target #1 for elimination should something seriously hit the fan.
Those issues aside most of the public is really not into the carrying of firearms by their fellow citizens. The more "in your face" it is done the more negative emotion it generates. No matter what the facts and our feelings on the matter there is far more likely hood of a larger group of people petitioning their lawmakers to eliminate carry than save it if the populace has it thrown in their face too often. That is why I and many others feel that OC is rarely a good thing and concealed should always mean concealed.
If you know the wind blows your shirt up when riding your bike than change the method of concealment. The guy you buzz around in traffic who is having a bad day and sees your gun can easily call in a complaint of a biker brandishing a weapon at him...