Or just not linking cause and effect. No doubt many left in a hurry in large SUV's doing 10 mpg wondering why it was happening to them.
Probably, although that seems to be a human thing, like touching the pan to see if it's hot then complaining when we get burned.
In this case, I wonder how many people realised the combination of decisions that were being made; they saw a chance to live in a nice place, and the fact it was a massive fire risk because of where the houses were built, how they were built, and the lack of water, probably didn't occur to them; why should it? This was all normal, it was all legal, so what could possibly go wrong?
At the same, there does seem to be a general idea in a lot of western countries that we can 'control' nature and don't need to think too hard about consequences. This is possibly amplified for people who are used to getting things they want and demanding to see the manager if they aren't happy.