What's the Deal with the Seal?

In P*mona they trust: The ACLU is threatening to sue the County of Los Angeles if it does not remove a cross from it's city seal. Three supervisors are supporting them. The ACLU might have a case, namely that the itsy-bitsy cross represents a violation of church and state, except that the cross is clearly there as a historical reference to the missions and--for me this is the kicker--they have no problem at all with the centerpiece of the seal, a representation of the Roman g*ddess P*mona. Logic says that the ACLU and its supporters think paganism if fine; Christianity is anathema. What's up with that? See the Los Angeles County Seal.