I don't think we disagree that many of the people who are termed fan boys add little but noise, but my problem is in accurately identifying them and in particular in then ascribing a single common world view and set of motivations to them as was being done in the thread above.
Plus being an apologist doesn't mean that you can't make a good point. Gruber could often be accurately described as an Apple apologist but I'd strongly take issue with the idea that he couldn't add to a debate on Apple. Similarly RMS when it comes to open source/freedom and others across the spectrum.
As with anything, argue with the point being made, not with the person, at least until you're absolutely sure you know them and where they're coming from far better than you're likely to through occasional interact on an internet message board.
And that's before we even get into the pejorative nature of the phrase "fan boy" and how you might as well just call someone a dick for the reaction you're likely to provoke.
Yes it's an interesting phenomenon but in terms of dealing with people who I may think are fan boys, I see no reason why there should be any reason why I should treat fan boys differently than I'd try to treat anyone else - that is take what they say at face value and engage them on that basis, or ignore them completely.