Many such lawsuits have ended in settlements outside of courts, so I'm guessing many legal claims have not been validated or invalidated in court yet. This can be good or bad of course. But now, if this guy goes to court, I'm actually concerned because it may give an unchallenged path to Nintendo's legal arguments and assuming the court decides he's guilty, there will be precedent of these legal claims having been vetted in court. Would that not be worse for anyone in the future who would want to challenge Nintendo's legal claims?
That would be a nice legal loophole for a corporation. Bribe someone to lose a court case without council, and then use that case as legal precedent for future cases.
Not arbitrarily though. If they are going to choose to ignore precedent then they have to provide a reasonable justification. E.g. the legal precedent is very old and is not fit for purpose in the modern era, or, the specifics of the case are different enough from the specifics of the precedent that It is possible to argue that it does not apply.
It also helped the US supreme court basically doesn't do its job anymore. Had the justice system worked as intended it would have been quite difficult to justify overturning it. It's not like anything new had happened or any new evidence had come to light.