I never made any justifications or claims of morality. I don't think pirating is some moral service in most cases, but I also strongly disagree that it's immoral. And yes, it may be a small percentage, but there are people out there pirating purely for archival sake. Archive.org has dumps of old games for pretty much every system. Lots of retro games would be unplayable now if people hadn't pirated them. Same with books and movies that go out of print. It definitely does help to keep the media alive.

My main point though was that I strongly disagree that there's any immoral or unethical about it, provided I'm not profiting off your work. You literally would never even have a way of knowing, if i kept a copy just for personal use. It's also definitely not theft, it's a civil matter and in civil matters you have to prove damages, which is impossible in the example you gave because there is no damage to you (or your reputation).