It’s become something of an in-joke within the greater games community that Nintendo is not an entity to be trifled with. Between DMCA notices against ROM sites and fangames utilizing their IPs, attempting to tango with the corporate monstrosity has a predictable end. It makes sense from a business perspective: Nintendo doesn’t want anyone marring the oh-so-marketable franchises they’ve produced over the years, and they certainly don’t want anyone accessing their creations without paying for them, regardless of the ability people have to legally play them.
Enter the bootleg. Where demand was not met by the official channels of distribution, pirate groups took it upon themselves to fill the niche. Creating their own cartridges with ripped games implanted, these groups would sell their wares on a black market at a far more affordable price and with a greater selection than typically available in these areas. Naturally, the companies these pirates were profiting off of were none too pleased with their actions.