Has the school asked for the exams to be returned, so they could be graded? I don’t know. I assume the graduate students wouldn’t turn them over anyways.
The university is free to make whatever rule they'd like to get around this, but instead go for maximum hurt to try to cut the legs off of this strike, and what is blowing me away is that this strategy by the university is working very effectively.
Even if they did average all my other work, I'd be pissed I put all that effort into something that has zero impact on my grade.
You're acting like the grad students have clean hands here which is clearly not true. They joined the union with the intent they would negotiate on their behalf. The union did so and promised to stop any wildcat strike. The students didn't like the job the union did, so they went on strike, violating the contract.
They didn't have a choice. The union then negotiated against their interests.
They likely joined UAW because they were already representing UCSC employees (bargaining power). Along with that comes the fact that union represents all members, not just you.