One challenge is that even in sucky workplaces, there always seem to be champions that will tell you how great it is.
If I hear people say they are (or were) miserable at a certain job - I tend to take their word when they say there's a reason for it. Your take seems to be... they just ne'er-do-wells who are looking for something to vent about. But that's the difference between you and me, I guess.