Is not the fallacy "argumentum ad bacculum" the "bottom line" of religion?

There is a way out: Do you let threats of eternal torment in Hell dominate your life? There is a way out.
God is a just God. What did God take away from you that He didn't give you, therefore, being a just God, that He owes you back? He owes you back your previous eternal nonexistence. At your Judgement before Him, if you want it, ask for your eternal nonexistence back. God, being a just God, will give you your eternal nonexistence back. Then, you will never suffer again.

To address your question, "religion" is too broad of a term for there to be one understanding. Surely there are those who profess the appeal to force kind of God you are presenting. In this case, yes, "believe in me and submit yourself to me or suffer for all eternity" is certainly an appeal to force. Perhaps, "THE" appeal to force.

There are definitely ad baculum arguments used in religion. However, it would be a misrepresentation to suggest it is a central tenet. Judaism and Christianity, for example, teach that free will led man down a path toward destruction, and that God/Jesus is our salvation -- a life preserver, not a stick.