But... there's literally nothing "good" about downloading an album. It's purely curiosity-based downloading. If there's an expectation of goodness, it's because the person has a preconceived notion of whatever it is they're downloading.
If this person has never heard of the media being downloaded aside from a commercial or something, they wouldn't know whether or not the media would be "good" until they listen and formulate their own opinion. So, no, your line of reasoning doesn't make sense, and stating the obvious wasn't really what you did.
You made an assumption that the reason the person downloaded the album was because of a preconceived idea the album would be good. You may be right. You most likely are. However, by saying you stated the obvious and that the person downloaded the album because they knew it would be good, is based solely on your perception of the album and the artist.