Seems simple: California is perfecty within its rights to ban a practice they do not agree with. The state is NOT within its rights to ban the practice in other states, nor to prevent residents of those states from marketing products made by use of that practice to Californians. This is precisely what the interstate commerce clause is about: otherwise there will be a series of state by state restrictions that say: if you don't make it our way, you can't sell it here.
You've heard of "Disgusted, Tunbridge Wells"? Well, I live in Holland Park and I've Had It. Up to here! An old curmudgeon, I rant and rave about things I read, see or hear in the News. Frequently sarcastic, irreverent and libertarian; often wrong - but never uncertain.