Deny what? You have shown two things and suppose there is some contradiction in asserting the one over the other. That is not so. Where is the contradiction?
Who forgives sin? God or the priest?
Yes. Catholics understand this. You do not. That doesn't mean they are "denying" something.
The priest acts as the agent of God. God is working through the priest, much as God used humanity in Incarnating Himself. When Jesus cures the blind, do you ask "is it this man Jesus who heals, or is it God?"
Of course not. You understand that Jesus is God.
"Most Catholics," as you say, stress that God is the one doing the forgiving because certain people like to think that we think our priests have power to forgive on their own. They don't. As you quoted above the priest does have the power to forgive sins, in the name of the Father, Son and Holy Spirit.
He is acting for God. Or rather, God is acting through him.
If I give you power of attorney, you have the power to act "in my name." So if you sell my house to someone when you have my power of attorney, did "you" sell the house, or did "I?"
Does God forgive sins or does the priest? The only answer is "yes."
SD