Some of the people in question do care, but know that their constructive comments will fall on deaf ears - but feel the need to comment anyway.
In those situations it is time to pack your bags and move on. Continuous commenting to people who you
feel will not hear you out, is a sign of insanity.
Whle the expression of their frustration may not be productive, that's not sufficient reason to dismiss them as lonely, no-life putzes. That's what I take issue with more than anything else. Their comments do carry a message, even if it isn't "constructive" in the usual sense of the word, and the people behind that message are likely as productive and normal as anyone who plays MMOs.
The message of an unproductive comment is one of attention seeking. Comments like "this game sucks" helps nobody (unless the topic is, asking for opinions about your enjoyment of the game). It in no way helps developers know how to fix the problem or even understand what the problem is. Thus it is reason enough to dismiss them all as pathetic attention seeking nobodies.