Maybe you should hang out with a different "everybody" if they systematically believe untrue things

Ah, one of those "everybody knows" argument that is on the level of "everybody knows that Napoleon was short".

It's not completely wrong but it ignores important context. The part you are leaving unsaid is that the vaccine reduced transmission even if it didn't prevent it completely. 80% reduction is a significant amount.

Wearing masks on top of that was the sensible thing to do.