Because when we decide on a goal for our technical work and decide on an acceptable code of conduct inside the project, our differences outside the project don't matter to our collaboration within the project. This is a core foundation of the Free Software and Open Source movements. (And it's worrisome to me that it's being eroded.)

My point is that this same setting aside of irrelevant (to the technical aspects) differences should apply to use of software in addition to development of software.