It really depends on the tone. There is a lot of feedback given in various ways. If someone people are very aggressive, it tends not to give a good impression.
I am on various mailing lists, mostly just to look for feedback and spot problems. Sometimes one person saying things is enough, sometimes only when many people say something.
Elsewhere the "faster horse" thing was mentioned. If someone gives feedback it can be various things:
- outright bugs
- hardware issues
- something that doesn't work right at the moment
- packaging problem
- performance (known or unknown)
- design/usability problems
All of that is useful to know, but there is not a one on one relation between this. E.g. a "don't drop fallback mode" criticism might be the result of something else, e.g. a hardware issue. Further, if someone doesn't like a nautilus 3.5.92 or even 3.6.0, it could be either a design issue, maybe not. Often what is expected that some suggestion must be implemented immediately. Not always possible... takes quite a bit of time to figure what the feedback really means. E.g. some stuff in gnome-shell 3.0.0 wasn't working nicely, but actually can be difficult to understand if feedback is in the form of "what are you doing?", "idiots", etc.
That's just interpreting feedback, after that knowing what to do, etc.
Not saying things couldn't/shouldn't be improved, just that the expectations are a bit high.
Note that recently I saw a few designers commenting on usability testing, saying that big usability tests (like Sun did) would be very welcome and is a bit lacking atm.