No. I am judging the parents on their actions, not on assumptions made of their intentions and hypothetical scenarios of what they "might do". That's the key difference you seem to be missing here.
The parents did not make any logical decisions, because they did use logic to reach their decision. They made assumptions, leaps of logic, out of ignorance and decided to act on them in haste, even though the driver had done nothing wrong. Just because you cannot see any other reason for them to do something doesn't give you the right to make assumptions and then render judgement based on them.
Judge people for their actions, not for perceived intentions.