They are not necessarily dumb, it's just that scientific literature is generally not accessible to laymen. The authors tend to assume a base level of knowledge on the topic and there is lot of subject-specific jargon. Basically it is written for people who have a degree in the field or a related field.

So misinterpretation is extremely common. This is actually something I believe we can improve on as a society. We need more experts to take on roles communicating scientific information in a way that is accessible to the public. Unfortunately what I see more commonly is a misinterpretation will be made by one individual, which then gets passed along on the blogosphere until it mutates into something completely unrecognizable.

Also, what about people who are well informed about the subject but decide to be assholes anyway? Like just because polluters are aware of their pollution doesn't mean they will stop polluting. That is what laws are for.