THIS...

Trust the doctors who tell you it's good to smoke cigarettes. Trust the nurses who spray your kids with DDT.

And THIS...

After all, there is no science proving these things cause harm. Therefore, they are safe. Anyone who claims they are harmful is not scientific unless they have science to prove what they say.

These are excellent examples that we should all reflect on.
Seriously, doctors used to recommend smoking to their patients.
Big Tobacco also spent millions to create uncertainty around whether or not cigarettes caused cancer. They supressed their own research and mounted PR campaigns to muddy the waters about cigarettes and health - all the while their products were killing people. Profits and greed drove these decisions and we would be naive to think that this kind of recklessness couldn't happen in this day and age.