I thought this would make an interesting forum topic.
I mainly emulate the 3DS.
My experience with emulation has always surrounded preserving older Nintendo games that are unavailable to purchase on the console. With the 3DS store shutting down, there's no viable way to get the games without buying second-hand from eBay. Some older mainstream games can have their prices hiked up by collectors which also makes it more difficult for the average person to acquire them. -None of these second-hand games generate money for Nintendo anymore (unless they add it to their cruddy subscription emulator), and with the possibility of the consoles dying emulation is a good solution to preserve these games.
So, TLDR; It's moral to pirate them from external sources given that no official ones exist anymore. And hey, at the end of the day, most videogame producers are multi-billion dollar companies who will never be impacted by the user base that emulates their products on different devices.