when you put up a sign that mentioned the bill of rights, you referred to something. you said, "the bill of rights is my flag".
when you refer to a piece of paper with words on it, and you do so by writing words on a poster pointing At that piece of paper, you've just made a symbol. you just drew on the lexicon of a nation: the bill of rights. it is a symbol of the US. it is akin to the flag. it carries with it a whole bunch of _meanings_. those meanings are fluid: you appropriated it one way (the NRA another way)
you had no qualms about wrapping yourself in that bit of american nationalism. and you really need to think twice about why you have a problem with flags if you can stoop to using the BoR as a symbol, because that's what you did. And, you did it as a way to say, "i'm a believe in at least one thing about the US, the bill of rights" (so don't shoot me)
were it to catch on, someone would make it more abstract and they'd turn it into a button, a flag, an adornment. it would become a symbol of belongingness (and,inevitably, exclusion)
kelley