Baloney.
Jesus Himself settled that issue. Is Jesus' word on it not enough for you?
And yes, we have a claim to say that Mary mother of God* is not correct because the Holy Spirit referred to her as *Mary, the mother of JESUS*. It takes a lot of chutzpah on the part of arrogant man to presume to change the word of God because they thought the Holy Spirit didn't do a good enough job in inspiring Scripture to be clear enough.
Catholics actually believe that JESUS IS GOD....I know protestants like to make up their own rules, but please don't change that one....