As I understand it, they choose purple because it is the color formed by blending red and blue. Their mythology is:
Blue = Lucifer
Red = Blood
So Purple signifies the offering of sacrificial blood to Lucifer.
I have been thinking this past year whether The Storm is going to lead Americans to consider changing the flag. Not only are the colors of the flag intended to mean the above, but the red/white stripes come from the flag of the satanic Tribe of Dan; and the 50 pentagrams are symbolically invitations to Lucifer to inhabit each of the 50 states.
Of course, these meanings are reprehensible to Christian Americans and even many non-Christian Americans. Before we honored the flag because we didn't understand the intended meaning of its design. We bought a silly story handed down to us in civics class about what the flag really meant.
Do any other Anons foresee patriots re-designing the flag as The Storm progresses?