Many people believed the housing crash wouldn't happen, many people often believe incredibly naive things. This should not excuse them. There were people among them trying to be voices of reason, they ignored them -- as they always do.

It doesn't matter that it was a terrible idea. The people who voted in favor got the poll bump they wanted and everyone is gone by the time the bill comes due.

Burn this pattern into your brain, it has happened hundreds of times and will happen hundreds more. Every single time people will exclaim "We couldn't have known!" That is simply misdirection, they didn't even TRY to know.