Why did I post that last one as a reply to someone else...? REPOST!
Looks like I have clarify this again since society insists on being wrong;
Critique: A teaching tool. You must be able and willing to show the artist how to improve. The artist must want to improve. "The best way to shade a sphere is thus..."
Criticism: Consumer advocacy. You must be informing others about the contents of the entertainment and if you think it's worth their time and money. "Two thumbs down!"
Opinion: It's all you, baby! People seem to appreciate a well-thought out justification for your feelings it but it's irrelevant because in the end it's nothing more than an expression of the meat pile between your ears. "I just don't like modern country music and I wouldn't go to your shit small town to try anything anyway."
What you get in comments 99% is opinion. Maybe it'll have something you can use to grow as an artist but you'd be well advised to ignore it because it's not for you. It's so the writer can feel like they matter.
The same goes for criticism TBH. The example up above of the film-maker telling a critic to make a movie if they think they can do it better? Stupid ego-saving move.