“What a great President someone who’s too cowardly to handle peaceful protestors will be.”
Trump handles all kinds of protesters every time he speaks on the campaign trail. Of course, you know that, but you did not want to miss the chance to be an ass.
He doesn’t know in advance they’re going to be there AND he knows those crowds are likely to be 99% friendly because the only reason to go is to see him. He was too afraid to risk not having the friendly crowd he’s accustomed to.