You're missing the point completely. He made a choice to protest while in uniform. A choice he knew would fuck up the rest of his life.
When someone puts on the uniform, they no longer represent just themselves. The whole purpose of the regulation is to prevent giving the image that one service member's views represent the views of the entire branch.
Regardless of your politics or morality, he didn't have authorization to speak for the entire air force, the DoD, or the US, which is exactly what he attempted to do by protesting in uniform.