I didn't mean to say that all windows users do this, or that users of other OSes don't do that, but based on my experience most of the people who work with just one maximized window are windows users.

I don't want to start an OS flamewar though, so I'm going to restate my guess as:

I'm guessing most of the wide screen "haters" are people who are used to the "one maximized app at the time" workflow.