The era of criticism is over. It is the end of the critic, the end of destructive comments, the long-delayed end of an era.
Critics have power as long as we're willing to listen to them. We don't have to engage them. We don't have to listen and we don't have to participate. Too often, when critics are decried, the decrier means on that s/he should become the critic. "Only I get to criticize music, because of my unique and legitimate position as the arbiter of taste." That is not my intent.
Obviously, music and art must be engaged and even discussed, or it is the end of music education. Otherwise, no one will ever know of any artist because no one will have spoken of them. It is appropriate to engage music in several ways.
If you are a teacher and the creator is your student, the constructive criticism is completely appropriate. Constructive criticism implies a power relationship. It should exist within that relationship or when requested, other wise, it is exerting authority where none ought to exist. Also, please note, constructive criticism. Saying "this sucks" is in no way constructive.
The way to engage art is to make art. It is very easy to say "this sucks" and to destroy and to complain about other people's endeavors, but it's more difficult to create something yourself, now isn't it? Engaging music with words, then, means talking about what is worth emulating in a piece. If we look at pieces as jumping off points, then learning from them to instruct our own music is beneficial.
And for those whose role it is to talk about music: If somebody invented something, say that. If somebody had made something great, say that. If something sucks, then don't waste our time by telling us about it. Talk about something that is worth talking about. Perhaps you're worried that there's a danger that some terrible trend will go unchecked unless it is criticized. However, it will not be emulated unless it's worth emulating. It will not be praised if it is not worth praising. Creators of suck will be met with a resounding silence. Their is no danger of something with no redeeming value taking over, unless, perhaps, you are thinking of Thomas Kinkade. Your position as newspaper art critic, angry letter writer, peeved grad student, gallery curator, arts administrator, university professor, or cultural-capital endowedness is not going to stop a consumer-driven trend. You can't make the unwashed masses like something or dislike something. Instead, they rather object to being thought of that way. Make something better, or you have nothing to say.