It probably won't make it to court because the devs cant afford it. Nintendo knows this which is what makes their actions basically bullying. They wouldn't risk losing in court when they can bully projects into shutting down.

Perhaps but unless there's something different about Yuzu I don't understand, it would have to go against established precedent in the US. For example, I assume Yuzu isn't providing the BIOS so how could it be breaking the law? Reverse engineering (clean room) has always been legal because there's no copyright infringement of the software and thus how else would Nintendo be protected? Meta-copyright? A patent?

I think this is just them trying to screw Yuzu by making them not even attempt a fight in court. Will it stop it now? No. But perhaps Nintendo has a method that would stop Yuzu currently and is trying to kill them before they implement it.