That's really not a safe assumption to make. The publishers may not have wanted to go after people but I wouldn't be betting on winning a court case against the

That's really not a safe assumption to make. The publishers may not have wanted to go after people but I wouldn't be betting on winning a court case against them over this. If decompiled code were fair use, you could take any application, decompile it, and re-publish it for free. It doesn't make any sense. Decompilation is a mechanical transformation, and the manual edits that come after to make it work do not significantly alter the nature of the work. It is clearly a derivative work of the original, so you're left with fair use arguments, and there certainly isn't any universal "well it's a game and it's just the code, not the assets" fair use argument.