I agree with your first point on how laws change. Why should we justify blocking traffic though?
The protest is about corporations giving people peanuts while the investors and C level employees take in millions. Not the ability to stand in the way of oncoming traffic. Those are two very different things.
The driver is absolutely responsible for his actions, but a group of people intentionally placing themselves in a road, be it entry/exit or just a main road are also partly responsible for their actions that led to their injuries. They know and understand what they are doing.
Hundreds or thousands of people walking out of these factories effectively stopping production speaks volumes, and definitely has an effect. Why tarnish that effect by acting irrationally and taking yourself out of the fight because you want to stand in the road?
This isn’t a single person with less control of a situation. This is a group of organized protesters trying to send a message, and knowingly obstructing traffic when the walk out itself is more effective.
I 100% support the UAW but I can’t openly justify either party doing what they did, the driver who is absolutely more responsible nor the protesters that were knowingly putting themselves in a position to get physically hurt. It does nothing aside from potentially hurt your message when you do that.
We are not going through a civil war, we are not at the point of people fighting with their lives (yet) over the necessity of basic survival. Both parties were wrong in this situation.