Why?

It really seems as if there are way way more people who believe that C0vid won't affect them than there are flat earthers.

Why are there still so many parties being hosted and why are people still attending them?

Ignoring these kinds of issues would definitely be nice. Just chalk it up as being natural selection rooting out idiots and moving on.

But then you need think of all the wasted medical resources. Hospitals have been and are still really low on space. An additional idiot could easily result in some other person not receiving the help they need in time.