User blog comment:TheO0032/What is the dumbest thing you have ever done?/@comment-27138615-20170602161724/@comment-26488146-20170605025600

A white knight's literal definition (not all of the many meme and Urban Dictionary definitions) is someone who comes to someone's aid, so by a blind white knight, I'm guessing that they mean that they always rush to some user's aid without learning what is actually happening.