From my perspective, it's not simply that people are dumb...They resist bad news (doom) with a passion.
My first experience with this was when I was in computer programming school in 1991 & was told about the Y2K problem. I explained the sitch to my friends & they found it quite interesting, & were all willing to discuss it...after all, it was 9 years away so there was no immenant threat.
As we got closer (say 1998) they started to refuse to hear of it any further...so for the most part, I stopped talking about it.
By mid 1999 (after NOT talking about it for quite a while) my friends & family members would bring up the subject just in order to verbally attack me...the closer we got, the more hostility came my way (even though I was still NOT bringing up the subject).
I can't tell you how many people quoted me as saying "it would be the end of the world"...no, I never said that...not even close.
This again changed in the last 2 weeks of 1999...people of all sorts (friends, family, even co-workers) said (with fear in their voice) if anything bad happened, they would just come to my house

They still had no intention of filling up a single gallon of water...they would just "come to my house".
Even my sis called me up & told me that the news stations had really let her down...They were all saying that you were a fool if you were preparring, then in the last week the news was saying that you were a fool if you had not prep'd already...she just couldn't believe how irresponsible the NEWS STATIONS had been.
That all changed back to ridicule & laughter once Y2K ended up to be a non event.
So what would you call this? Stupidity? Lazy? Denial? I do agree that it's totally bizare behavior, yet very common.
I don't discuss P.O. with anybody (except here)...why put myself in harms way? Y2K taught me this lesson well!
Quis custodiet ipsos custodes.