Cultural drift is full of examples of things that, because one cannot point to what they believe to be a significant enough correlation between cause and effect (the ratio is too small), we buy into the notion that those causes are too insignificant for effect. Thus convinced, we do and say nothing.

So we shrug at TV shows that educate us to accept the unacceptable.

We shrug at pornagraphy because we can't point to a one-for-one ratio of obsession to bad behavior.

We shrug at industrial causes for global warming because the cause-to-effect ratios are too insignifcant for positive measure.

However...

We all know that, by a pretty substancial ratio, most acts of sexual intercouse will not result in pregnancy -- but we would never dismiss the connection of the two.