"I place ideology above party loyalty. It is true that I will not vote for any Democrat under any circumstances, not even if they seek my vote for local dog catcher"
But what if the Democrats embrace policies that comply with your ideologies? If you value ideology over party loyalty then that would be a circumstance where you should vote Democrat. (inb4 'but democrats will never embrace my ideology!' it's still a possibility).
"I place good play over team loyalty. But I will never support any team other than the Patriots!"