What did I get flipped?

Legality vs morality

Why wouldn’t torrenting the source code of proprietary software would be a legal issue?

It would be a legal issue. But it's not a moral issue, which is why so few people are showing sympathy for Nintendo. They lose nothing if someone gets a copy of the code - there's no victim. They do however have a LONG reputation for weaponizing the legal system by attacking fans with frivolous lawsuits - those DO have a victim, and are therefore a moral issue with Nintendo as the aggressor.

But regardless of context, again don't conflate legality with morality. Ever. History is absolutely stuffed with atrocities that adhere to established law, that doesn't make those atrocities okay. Videogame code is pretty minescule compared to legal attrocities like slavery or the holocost etc, but point remains that the law in-and-of-itself doesn't mean shit.

Also fuck Nintendo.

I think their point is that you said "but I am overall against these practices, since they are just illegal", as in you're against something because it's illegal not because it's immoral