No, his dinner party was goat-fuck stupid and utterly hypocritical. That said, the science (as evidenced by the very large number of practicing doctors and nurses supporting masks) indicates that wearing masks, especially the transmitter, but also the potential recipient of infected particles, reduces infection significantly. You can look at the infection profile of the vast majority of the states, sorted by the strictness of their anti-COVID measures. They correlate well. It's not perfect -- Rhode Island is having a big spike, and they're reasonably strict. But by and large they do.
That's what science is. Not a promise of one-to-one perfect anticipation, but evidence showing that following a particular path is more likely to lead to one or another outcome in a limited set of outcomes.
Wendy P.