I can see both sides. With movies, if it's a good one, I can watch it over and over, and appreciate the acting, the writing, the cinematography, everything, all over again. To me, it's very much like listening to a favorite piece of music again and again.
With music, that first listen is very important to me. I want to hear the song unfold naturally, I want to be surprised if there's a key change or a mood change or something, and when I think they're going to come back to a chorus or verse but instead it goes into an instrumental, I want to be surprised by that, too. When I was younger and had more time, I'd sit and absorb it all while listening to it; reading the lyrics and liner notes, checking out of the pictures and/or artwork. Today, I listen to most "new" music (new to me) in the car, and it's great to just let it unfold. I don't even know the song lengths. When I get to the epic, I don't know it's the epic, I just keep getting blown away by the changes and the different parts, and later I look and it was a 17-minute song or whatever. I let it take me on the journey.
On a similar note, if everyone's raving about the guitar solo or the bad vocals or something in a particular song, when I get to that song, I'm going to hear it and think "eh, it's not that bad" or "eh, it's not that good" or maybe it is that bad or good, but either way, I'm going to be comparing my impression with what others have said, not just forming my own impression first.
So... for those reasons, I try to keep music "unspoiled" similar to how I try to keep movies unspoiled. But I also understand that these are music discussion boards, and I can either skip over the discussions I can see are going in that direction, or avoid them completely. I don't go to IMDb and complain about people spoiling movies that have been out for years, and I wouldn't complain about people discussing new music here.