Sounds like walking away is the healthy thing to do. Sometimes these things can't be fixed.

I know of a couple of people who I have written out of my life because their stance on a certain topic so negatively colors my perception of them that I can't in any good conscience continue to interact with them. Not saying that is what happened in your case, but they've made a choice, for right or for wrong, and it is unlikely you will change their view of the situation.

Not every break in a relationship can, or even should, be fixed.