Amid nonstop grilling by U.S. senators about the nation’s shambolic mail system, Postmaster General Louis DeJoy had jokes. After Sen. Ron Johnson (R-WI) relayed a constituent’s question about the manufacturing of ubiquitous blue mail boxes on America’s street corners, DeJoy cracked that Johnson’s constituent wouldn’t want to steal from one of those blue mailboxes … would they? “Pardon?” Johnson said. “It’s not somebody who wants to break into ’em, is it?” DeJoy repeated with a smile and a laugh. “I don’t think so. This is a cooperative type of question,” Johnson said, not seemingly amused. Cur…