Seems to me he just had a stage presence they appreciated at the time. So basically #2: >They were clapping for themselves >the audience is mostly comprised

Seems to me he just had a stage presence they appreciated at the time. So basically #2: >They were clapping for themselves >the audience is mostly comprised of people who have absolutely no doubt that they themselves will someday be on stage Every audience is different and there's no accounting for taste. When preaching to the choir it's no surprise they respond positively.