How? Simple. They don't consider themselves evil, they consider you evil. They believe they're morally superior to you, in every aspect.

Read Haidt's The Righteous Mind to gain insight into the differences between liberals and conservatives. His Moral Foundations Theory finds that liberals have fewer morals than conservatives. I mean: Liberals literally do not consider as moral issues things that conservatives believe to be moral issues.

This is why I've been saying that liberals are morally deficient. And they don't see their own deficiency. (Akin to the Dunning-Kruger effect, which shows that dumb people don't know that they are dumb simply because they're too dumb to make that assessment.)