Sometimes, the only reasonable response to retarded enemies being retarded is to bury them in so much retarded bullshit in one shot they just can't cope with it. This is absolutely one of those times. There is no "grown up, mature" response to this degree of retardation capable of producing "No Kings" as a protest concept in a democratic republic with an elected official operating at peace time within the limits of his office.
Seriously -- an entire cadre of mostly-paid agitators are claiming with all sincerity that a duly-elected official (who achieved a democratic victory in such a landslide it'll still be talked about in a hundred years) literally doing what he was elected to do (and to the overwhelming approval of his voters and supporters), fancies himself a "King," essentially calling him a dictator using a shorter word more of them can spell.
There is no "reasonable" or "serious" retort to that kind of bullshit. The best response really is to just ... dump lots of bullshit on their heads. That's what this is, and it's glorious. I say drown 'em in it.