I think Joel is pretty fair when it comes to MSFT. Sure he's an alum but he's not a fanboy by any means. He uses MSFT technologies because he knows them best and it works best for his business.
I suspect the grandparent post was being a little sarcastic. My impression of Joel's opinion on Microsoft is that it's gone downhill after his time there. Note that I'm not implying Joel thinks it's _because_ he left, just that the essays of Joel's that I've read seem to show a consistent dissatisfaction.
OK, I was just confused because I had also noticed that consistent dissatisfaction and couldn't tell if I was crazy or if elgringo was being sarcastic. Thanks for letting me know I'm not the only one!