Let's concentrate our fire (on THIS thread, anyway) on the REAL enemy: the God-less ACLU!
Sorry, I got distracted by earlier comments.
I don't think the politicians have a moral right to change something like a state seal, with a long and honorable history, without having some very good reason. Unlike banana republics and countries that experience constant revolutions, America is not in the habit of changing its flags, seals, or symbols on the whims of politicians.
Their reasons would seem to be that they are ashamed of California's oil wealth (which helped build the state in earlier days), ashamed of the traditional white female figure of American Liberty, and ashamed of California's traditional religion.
Probably you are right to focus on the cross, which was certainly a central symbol of California's history as well as the dominant religion of the state and country. Among other things, it's a kick in the face of California's Hispanic inhabitants and past history (an angle that ought to embarrass them).