As someone who read the original V for Vendetta when it came out, it has always bugged me how it is now being used. The truth is both David Lloyd and Anonymous chose it, purely because they thought it looked cool and not because it represented anything else. Which is easily believed, given that what it actually represents is religious fundamentalists trying to violently usurp the power of the state in order to replace it with a more ominous and draconian power in the form of the Catholic church and ultimately the Pope, who, in the 17th Century wasn't known for being a tolerant libertarian. The fact is, it is to our benefit that he failed or we would have been under a far more restrictive yoke that would have at the very least delayed our transition to a so called parliamentary democracy.
In fact it is the same as if in 100 years time people started wearing Osama Bin Laden masks as a symbol of freedom and liberty. Even in the comic V is not put forward as a hero, but is left as an ambiguous figure who could be anything from a psychopath to a terrorist unfettered by an ideological direction. Unfortunately Hollywood, in the form of a global media corporation has clouded our history with its own iconic misrepresentation of stories, both Guy Fawkes' and Alan Moore's, for its own profit, leaving an entire generation who probably have no idea who Guy Fawkes was or what he actually represented.
It still looks cool though