"...'300' is just a forum hot button..."
A better way to look at it is that "300" is exposure. I didn't even like the film, but the workout was mentioned in another forum I frequent, which led me to a Google search, which led me here. It looks like I'm not alone.
I think CrossFit is the program I've been looking for all my life, not only for the exercise and diet concepts, but the online community that supports it as well as one another. Anything that brings that to a wider audience is good, fad or not.