Will respond with something a friend told me after criticism of my work: "Really, if you're trying to improve something, that's more respect for the work than coddling its deficiencies."
I can sympathize with that position, to a point.
But as Mal said in Serenity: "They'll swing back to the belief that they can make people... better. And I do not hold to that."
The point being that "better" and "improve" can be quite subjective, particularly in the context of other people's stuff since you can't always guess at their intent. You might not like a particular part of a particular song, but there's probably A Point for it being there, and it's quite possible that you not liking it may correspond with you not understanding The Point behind it's presence.
Not discounting the possibility that a given thing might just be stupid.
Which, of course, is a objective measure.