Foss is an Idealogy
People tend to try to sway others to their beliefs. Some go too far; others do not.
You get the same from Microsoft, except they do it indirectly by making their products the standard through shady manipulations and marketing.
Please, I don't want to convert you. Be the windows user/programmer/administrator, I don't mind. I've had enough with people shoving in my face 'how great windows is?' and 'how awesome the community?'.
In developing nations, Linux has its place, it helps cut down overhead & startup costs. But as far as capitalist nations goes I don't really see where it has it's place. Every user has their style, some though I think incorporate more than they should of their ego or passion such that it overshadows and detracts from the meaty knowledge contained therein.
In the end it comes down to what you want to use it for, what you want to do with it, and weather or not it will accomplish your goals. People who choose Linux choose it because they feel it's got everything they could need. People who choose Mac feel the same. People who choose Windows also feel that Windows accomplishes what they need.
If that wasn't true people wouldn't stick with it. They'd be shopping around. Oh sure you can make the argument that maybe person x doesn't know about feature y in OS z, but at that point you're just assuming that they care, or need that feature. Maybe they do, but chances are much more likely that if they're able to get along without it now, they don't need it because it will just complicate what they're used to.