While the fallacy you're describing is an apt description of 90% of political bitterness, it is effectively impossible to force people - even reasonable people

While the fallacy you're describing is an apt description of 90% of political bitterness, it is effectively impossible to force people - even reasonable people who acknowledge the sins of both sides - to ignore the nigh-universal opinion that "one of them is worse". I honestly am not sure how to get around that, especially considering that it's almost certainly true by many metrics, regardless of "which side" it is, since it would be an amazing coincidence for both sides in any context to express goodness and evil in effectively equal amounts. The tendency to take binary sides on a gradient issue is just too strong - even people who see and acknowledge the gradient still effectively choose sides in most conversations. Edit: It's almost as if you have to let each side feel that they are correct that "the other side" is indeed worse, but also communicate to them that it doesn't matter in the big big picture, and pursuing any manifestation of that opinion is counterproductive.