I think a lot of the people that completely write the UAPs off as a hoax, or dismiss them as a mistake, are at least slightly scared by the implications of what these observations could mean.

The UAPs seem to break our understanding of the laws of physics, and our military and intelligence communities seem to be genuinely stumped by them. Even if these craft are being controlled by an unknown government or group of humans, it is still terrifying that they managed to make such advancements while hiding them from the rest of the world.

I have always been pretty skeptical. I won't even try to begin to claim I know what these things are, or where they come from. Despite that, the evidence that they exist is getting pretty hard to deny.

I just can't think of another reason why so many people want to mock and avoid the topic, besides fear and angst. This could be one of the biggest discoveries or paradigm shifts of our entire history as a species, with or without aliens being involved.