This is a major problem with lay people understanding scientists. Scientists very often speak in terms of probabilities, and are generally the least dogmatic sorts of persons. People with no background in science will often demand certainty. I've always thought this was why the excluded middle fallacy ("Either you're with us, or you're against us.") is so popular with those on the right of the political spectrum, as studies have shown over and over that the higher your education level, the more left/liberal you tend to be.
This does not fit my experience at all and certainly not my experience of sciforums. They may, as professional scientists, in the context of their work, speak in terms of probabilities. But otherwise... I guess if you could back this up with some research, I'd be more open to it. This seems to me confusing an official epistemology for how people in fact participate in society.