I've refrained from saying anything regarding the actual copyright debate because I couldn't word it in a non-inflammatory way but I'll just say that if there's any requirement or even a strong compulsion to go "legit" popping up, I'd rather just never mod FS2 again than deal with the hassle.
I get it, some of you actually want to use your work as a stepping stone to get into game development, make a portfolio or something. Some of you have this story you want to tell everyone, and this is your way to express it. For achieving those ends, going "legit" is probably a worth cause. But not everyone mods for that purpose. I mod FS2 because it's fun (usually). I don't make a campaign to tell a story to anyone else - I do it to put a story I have in my head down so I can go experience it in a tangible form not just my imagination, or sometimes its thrown in as an afterthought. I don't care if nobody downloads it - I don't have any ego to feed, or an end goal to all of this - sure, it makes me happy if other people are having fun with what I "made", but that's just icing on the cake. I'm perfectly happy with never releasing anything ever again if there's going to be some requirement on what music I put in, because I put the music in there for myself to listen to while I test/play the stuff on my own. People were interested so I shared. I can always stop sharing. Saves me the massive hassle of testing and making sure things work on other people's systems and all.
If it's really so wrong to share ripped music and that's what the community agrees on, then fine. It won't be. Along with everything else.
I could say a lot more, but that'd just risk me coming off as a lazy asshat, so I won't say it.