If this ever happens to you, use your cellphone to take the picture of the “young man”. Then, immediately e-mail it to yourself and others. Do this several times.
It is amazing how these fascists don’t like their photo taken and spread.
Valuable advice. It's a good idea to have high-quality video of any meeting, and the people there, because you may not know ahead of time who is going to cause you trouble, and once he starts causing you trouble, you may not get the opportunity to get his picture.