Because they don't have to be.
In Canada, the mandate is ignore the disturbing truth. It's easier.
Canadians love this mantra.
Discussion
It justifies their docility.
You can tell them anything, really. As long as it's broadcasted through government funded channels - they'll do anything.
Meanwhile i'm sitting here, and with each passing day watching what used to be perfectly good clear blue sky eyes, get cloudier and cloudier.