It's probably a wise decision. Since 'false' Trump supporters have already gotten
 into his rallies, the danger of One pretending to be a Trump (and 2ed Amendment ) supporter, and carrying a gun, is an unacceptable risk.

But Whom are these "angry people" of which you speak? That would be the Trump Protesters, not the (true) Trump Supporters. IIRC, there were only two incidences when a Trump Supporter was 'inappropriately physical' in interacting with a Protester, yet  innumerable incidents of angry, violent Protesters.