Care to elaborate? His guidance seems to be reasonable and consistent - while it should be taken with a grain of salt (some of it feels anecdotal rather than factual), I don't find it unhelpful, as you posit.

Joel isn't outright dishonest, but when he presents his views he usually does it with the intent of improving his business, or rationalization for his business decisions - so there's a strong slant to his talks. You can see this in a lot of places - Everything from his talk about 'great work environment' - "and that's why every programmer at Fog Creek has two monitors and their own office!" to his suggestions of how to hire the best programmers concluding with "That's why you should use StackOverflow Careers". When he's not outright pitching his company or products, he's rationalizing decisions. Clearly, Ruby on Rails was too immature for FogBugz - that's why his team developed a custom programming language to power BUG TRACKING software.