I watched the video of the events inside the theater. Javier Munoz's speech to VP-elect Pence was polite, erudite and, I thought, very well done. One may argue as to whether it was appropriate, but presentations by the cast at the end of performances to promote causes have long been common in New York theaters.
I see nothing there to apologize for, or to be insulted by. He made his plea well. The demand that he apologize sends it's own message, in my opinion.