That Los Angeles County Seal: More on the cross removal from Cathy Young here:

Many Americans today believe that secularist forces in this country are implacably hostile to all things religious, particularly Christian, to the point of wanting to purge our culture and our history of all traces of Christianity.

This exaggerated perception is exploited by religious extremists who really would like to undo the separation of church and state—who believe, for instance, that same-sex civil marriage should be illegal because the Bible condemns homosexuality. When secularists go after a tiny cross on a county seal or Christmas decorations at a firehouse, they lend substance to the "religious persecution" complex — and play right into the extremists' hands.

Of all the arguments for not making a secularly bowdlerized seal, this one is the best, I think. Making a point that secularism can be reasonably accomodating goes a long way to undermining the religious right. If you take a look back at my posts on Judge Roy Moore's Ten Commandments controversy (here for example, point 1), I think you'll see that this was the point I was making. I personally opposed Moore's motives and actions, but I worried that the argument against him had to be a little more sophisticated than, "Separtation of church and state, dude."