The leader of the United States encouraging law enforcement and the military to shoot American citizens for looting, that's the line.
That's an extremely literal interpretation of his words. Most people would interpret that phrase to mean "you better think twice before looting because I'm not going to sit idly by and let you do it" but in the form of a vaguely threatening, yet catchy rhyme.
Yes, which is better than a reasonable interpretation of his words would show them to be, because going beyond a mere literal reading to consider the deliberate historical reference and the implicit subtext makes the statement worse, not better.