Other than that, i don't think Facebook has much legal ground if the facts presented in the blog post are everything to the story...
IANAL, of course
I went to the EFF for advice mostly, did I need to comply with the takedown? Should I be concerned that I couldn't meet all of the ridiculous demands (they wanted personally identifying information about everyone who had downloaded the extension!). EFF's response? In summary "We're not sure on this one… But can we blog about it? This may or may not cause you more problems."
I didn't hear from them again after I asked them to keep it quiet for the time being.
Yes there are cases of the "small man" being able to fight back and win. I doubt its par for the course and it's one of the severe drawbacks of our legal system in the US