I've been a part-time cultural critic for...a long time, and I couldn't agree more. I've always tried to do two things with my essays: make them as creative works in their own right, and always recognize the subordinate nature of criticism. This both makes me sympathetic to the artist (as someone who in a lesser way is presenting a work of my own) and also less prone to taking the all-too-common Superior Stance of the critic.
If a work is particularly bad, I'll generally just leave it alone, unless the artist has presented something that is obviously cynical and pandering, or otherwise obviously derivative and parasitic on the work of better artists. In those cases I might get slightly snarky. I try to control this and tone it down, because even derivative works are risks, and usually somewhat naive.
If the artists' ambitious goals weren't met, and I think I understand them, I try to lay this out in as constructive a manner as I can.
I can usually only accomplish good criticism by immersion -- repeated (dozens of) listens to a record for instance, over a period of days, writing/typing out lyrics by hand, listening to all the artist's previous records, reading as many interviews as I can and just trying to get my head in the "space" of the record. At some point I get to a place of sympathy where I get into the "soul" of the record and I really have something to say, that isn't just a first impression, nor a knee-jerk reaction, but as close to deep understanding as I can get. It's really hard work, even for just a 150 word review (which is one reason I don't do it often any more).
It's rare to get that kind of perspective on a HN comment, "Show HN", or some blog post linked here. But even with the noise that's emerged over the last few years as HN has grown, I can still find the really constructive comments and learn as much as I always have. I just have to look past the frustrating drive-by comments, the throw-away accounts and the axes-to-grind. The signal-to-noise isn't what it used to be, but in general there's just as much signal, but a lot more noise to have to overlook.