The parents made misguided assumptions of someone else and dictated how that person could express themselves. Fuck those parents. Period. Your wild logic to justify their behavior is utter bullshit.

Assuming you tried to avoid a double negative and instead meant "There's nothing wrong with them making assumptions of other people":

No, that's the opposite of what I was saying. You clearly lack reading comprehension based on this entire thread., so no surprise you misinterpret me. There is everything wrong with making assumptions of others. It's a bad habit people need to stop doing. People who do so are in the wrong. Period.

There's no difference here between the amount of assumptions made by the driver and the parents.

Except there is, because the driver was making no assumptions of anyone. His actions were not based on the decisions of other. He was simply expressing himself in the way he saw fit. As he has ever right to do. Every individual on this planet has the right to express themselves independently of how others around them might perceive them. Only the parents made assumptions of the man and his preferred method of personal expression and then acted in a way to deliberately restrict this man's ability of personal expression.

The following argument is based on the parents being justified in their assumptions, which they weren't, so this argument is invalidated. That was not a reasonable assumption. It was an ignorant assumption rather than actually observing the actions and seeing that no child was harmed.

unfairly forced this man out of his position

No, it isn't an assumption. Read the article, it is directly written in it. He no longer drives that route. That route was his position, which he no longer occupies. The rest of what you said is irrelevant to my point.

The driver caused zero harm.

No, this also isn't an assumption. It's the negative. Until you can prove with evidence he did harm, then the negative is always considered true. This is called the "benefit of the doubt". Learn it.

forced either to wake early and walk to school or contribute to the emissions in their air.

They were not forced. Parents were perfectly able to choose to continue letting the kids keep riding the bus. The harm of emissions from not letting the children take the bus is the fault of the parents, not the driver. If the parents can't drive their kids to school, then they should learn to cope that other people have the right to be different. Don't shift the blame.