Originally Posted by
jon c.
I don't think there are a large percentage of motorists who are that ignorant.
I won't argue the percentage, but it's certainly a sizeable one for a very simple reasons. First, assumed converse is a very common error. Second, here it's also a convenient assumption because it reinforces what they already want to believe. Logic doesn't matter, people tend to selectively use whatever conveniently reinforces what they already (or prefer to) believe.
So, for those drivers who already get along with cyclists, it's no harm, no foul, but to those who are the likely problems, it "supports" their assumptions.