I just explained how it is different. Political ideology is a choice; sexual orientation is not.
In both cases the discrimination would just force me to pretend to be something other than I am.
I don't disagree about color, but the way how you can or cannot force people to avoid visibly and openly living their political identity OR their sexual identity is exactly the same, as it is for religion. It's always outside force, forcing you to pretend to be other than you really are.