The only thing I have seen proven is that some anti-Catholics believe that hysteria and repetition are effective and legitimate means of establishing truth. It does, but not the point they think they are trying to make.
"Vikings prayed to Oden as the "all Father." Were they praying to the same God as Christians and Jews?"
I reject the premise of "same God" because there is only one God. The concept of another God is only an abstract. The desire for God embodied within Natural law and is written in the human heart, because man, even the Viking, is created by God. God never ceases to draw man to himself. Only in God will he find the truth and happiness he never stops searching for. That search does not empower any man or men to create an actual god or gods, only to imperfectly fill the void.
According to St. Thomas Aquinas, the natural law is "nothing else than the rational creature's participation in the eternal law". The existence and nature of God is the foundation of the eternal law. When praying to Odin (not Oden) the Vikings were participating in the eternal law rationally, but imperfectly.
Once again, explain exactly who this "Rome" is that you are so fixated on.
Reject whatever you want. You've just been proven wrong. "Praying to one God" does not equate to praying to the true Creator of all that is and ever was and ever will be, according to the Holy Scriptures, who is and always has been and always will be the Triune God - God, the Father; God, the Son, Jesus Christ and God, the Holy Spirit.
That is the true God. The "only one God."
God never ceases to draw man to himself.
And this is the papist conceit which would have God calling some men to Himself and some men to an ersatz facsimile of Himself.
Idiocy.
But this kind of mush is what Rome teaches so that Rome can incorporate various pagan faiths and rituals and beliefs, blending them into its own peculiar, anti-Scriptural puppet show/property management company/criminal syndicate.