[MrMatters]

I'm probably not the average MU user, but 99% of the stuff I used it for pretty legitimate. Game files/recordings, map files, photo albums people were too lazy to upload one by one, personal videos between friends we didn't want to upload somewhere public like YT, etc.

This is all anecdotal and I probably agree with you that the average user most likely just used it to download music and pirated content, but I do think you're overlooking a ton of legitimate usages as well.