If you are prolife, you ideology is unchangeable. Same for us on the prochoice side. If you are antigay in all its manifestations, like so many commentators on this website are, you are inflexible on gay marriage. I am too on gay marriage. It's all black and white on both sides, There is nothing to be done for either of us in our groups, but hope our side wins. So far, my side is, thankfully, in both regards.
The rabid Left and rabit Right are also inflexible in their own ways, from the environment to guns, from entitlements to tax rates. There is not black and white there, so that is where the compromises must reside. That is why I choose freely to vote where I think I will find the most compromise.