I don't think that these HN posts can be dismissed as cyclic griping and finger pointing / laughing.
1. Any company that produces bad UI should be called on it, particularly when that UI is going to impact such a large number of people.
2. I have a sense that it's not just anti-MS griping because, after all this time, after seeing the ascendency of design centric products, we find MS is still incapable, on an institutional and management level, of improving. Indeed they are getting worse at this.
3. If MS had produced something truly impressive, I think you'd see some honest, if not muted, clapping from even the anti-MS crowd. I'm no fan of MS (or Apple in many ways), but I'm a fan of trying hard and doing good work. This seems like neither.
P.S. You are right to point out Apple's failures. iTunes is a beachhead product that they are terrified of abandoning or altering lest it kill the golden goose ecosystem (they have no qualms about killing the golden goose of other people's ecosystems, cf the pro apps series, in the name of usability, though I think their success record there is spotty at best). It is an experience nightmare as well. I also hate the direction of the faux-natural-ui garbage in iCal and elsewhere in the system. Apple isn't hitting all homeruns on the UI front, even if they have raised the bar.
edit: spelling, more words.