I think the applause was sincere. Who was in the audience? Those most likely to approve of the destruction of the USA. The self appointed elite who think they should rule us lowly serfs, government apparatchiks who love to see government grow, big time Democrat donors who get the thrill of rubbing up against sleazy politicians, etc. and there are few if any politicians sleazier than slo joe.
The types who voted for this cretin approve of everything he has done. Caring about supposed polls is something only trivial people care about. Little people. Soon to be slaves.