The media just added that nonsense in for some drama and pile on because we all know that Trump supporters are racist, don’t ya know by now.
This allegation was made at an earlier protest by a Congressman and I don’t recall who but someone put up a $100,000 challenge (or something on that scale) to produce video to back up the assertion.
Larry Elder has discussed it on his radio show (I don’t recall what year or the specific subject of that protest).