I don't doubt that this often happens. However, what is just as clear to me is that there is a group of people who leap to this assumption, especially when certain brands are mentioned (and for the record KIS, I'm not suggesting that you're in it). If I had a nickel for every time the reasoning behind my own brand choices have been suggested to be a product of "fancy marketing hype or fanboy-ism," I'd have... well, maybe just enough to buy myself lunch.
What I don't understand is why anyone should care so much. If someone buys a drum kit and they are happy with it, why should their reasons matter to us? I ask the question because I honestly have no answer. Yes, I get the whole part about growth and awareness through shared experiences, but I'm referring more to the tearing down that also happens.
Which leads me to these two groups: people who make brand choices for seemingly shallow reasons (relative to our own points of view, of course) and those who criticize them for it. I see the latter as being more problematic. It it possible that this is a contributing factor as to why the "Show Us Your Kit" section enjoys more activity? I think so. Those threads strongly trend towards celebrations of our choices rather than the reverse. A few outwardly negative contributors aside, those threads are a great time!
With all that said, my advice to anyone contemplating a drum kit purchase is to try things out to the best of your ability, make a choice with your mind and your heart and then post lots of pictures of it in the Show Us Your Kit section when it arrives. You'll probably gets lots of great feedback and might not ever hear from the guy who points out that you just made a stupid decision for all the wrong reasons.