Well that came out of left field.
It came from Wrong Paul insisting in 1991 that our use of armored bulldozers and tanks with plow attachments to clear trench systems during the Gulf War was tantamount to war crimes.
Bernie has never gone as far in his loathing of the military as Wrong Paul.
You could say that it came from left field because aside from reigning in the fed Wrong Paul is and always has been an unabashed leftist.