Words mean things. This writer needs a dictionary.
The unarmed is sarcasm based on Bidens comment on police training: “Instead of standing there and teaching a cop when there’s an unarmed person comin’ at ‘em with a knife or something to shoot ‘em in the leg instead of the heart is a very different thing.”
https://www.foxnews.com/politics/police-biden-cops-knife-leg
Nobody commenting seems to have picked up on the fact that the author is calling him “unarmed” to mock Joe Biden’s statement about how cops should deal with some one who is “an unarmed person coming at them with a knife”.