Why? Whole Foods is great. For example, if you're too busy to pack your lunch, there is a great cafeteria where you can get simple food with lots of veggie options at whatever portions you want. The quality of the meat, bread, and produce is a cut above (though I hear it's just par for course in terms of what you can get in "normal" EuropeN grocery stores).
I think the complaint is that Whole Foods is selling you the idea that the small subset of "healthy" brands they are promoting is what you should be exclusively eating. They're a great store as far as options, but the Kool-aid they're pouring can be a little annoying at times.