I saw that it was at a private hotel reception room, as opposed to a school aud or other public venue, so normally somebody is paying for it, and I assume there is a guest list.
Was it actually an open question town hall type forum, or an open speech (where shouting him down would have gotten him removed) or a private fundraiser-rally for contributors where he would have been a party crasher?
His actions warranted removal from even an open town hall meeting. But he only deserved the rude exit (as opposed to a simple escort out) if he was a party crasher. Having said that, the clip I saw was obviously cropped, and he could have been shouting and refusing to leave for quite some time before he was physically removed with prejudice.