You know it's kind of like Amway or Earthlink or one of them. For every person I get to worship Mary I get one free month of grace.
Actually, what is it is that the "is" in "Jesus is God" is not commutative. If I say "Jesus is God, that is not equivalent to "God is Jesus", even though God doesn't come in pieces or parts.
But the very nature of your disagreement is consistent with our assertion that to say "Mother of God" about Mary is a Christological and Trinitarian issue.