Sounds like a kind of dumb thing to criticize, then. Picking the side of Martin Luther King Jr. on civil rights is…uh…kind of a difficult position to argue against.

It's an example of when "not being tribal" is wrong, because one side wanted to keep denying civil rights to a group of people. The correct side was to protest and put pressure on the system. Take the war in Ukraine. There isn't a middle ground between resisting Russian aggression for Ukrainians and fighting back. You either resist, or you get conquered. Not all issues and situations have some happy middle ground where both sides are equal parts wrong/right.