This insult tossed at Protestants is in no way what Protestants do or believe, nor is it what Scripture says to believe or how to behave.
Christians believe that the Holy Spirit indwells them as a free, merciful gift from God to His children. The Holy Spirit guides our reading of the Scriptures, making known the truth of God, so that the words themselves truly become "spirit and life."
"It is the spirit that quickeneth; the flesh profiteth nothing: the words that I speak unto you, they are spirit, and they are life." -- John 6:63
The words, made knowable by the Holy Spirit, penetrate our hearts and minds and redirect us from the darkness to the light.
Do all Christians get everything right?
Nope. But as Calvin reminded us, without the Holy Spirit as our guide, the Scriptures are just ink on a page.
"For by the Scripture as our guide and teacher, God not only makes those things plain which would otherwise escape our notice, but almost compels us to behold them; as if he had assisted our dull sight with spectacles." -- JOHN CALVIN "Commentary on Genesis" Vol. 1
Therefore, the "sole and final interpretor" is God, the Holy Spirit, refining our understanding and renewing our minds to the truth of Christ risen.
The visible church was created to help men know the truth personally, not to define the truth for them nor to dispense (or withhold) God's grace. The word of God by the Holy Spirit does that, as the Christian church, testifies, and it does that for all who have been given, freely and mercifully, eyes to see and ears to hear.
As validated by YOPIS?
Christians believe that the Holy Spirit indwells them as a free, merciful gift from God to His children."
Except of course when those involved are Catholics who arrive at a different interpretation and conclusion than YOPIS?
Therefore, the "sole and final interpretor" is God, the Holy Spirit, refining our understanding and renewing our minds to the truth of Christ risen."
And then only as codified by YOPIS?
Your entire response is aimed at denying any authenticity for the Holy Spirit's guidance when it conflicts with YOPIS.
[There is] therefore now no condemnation to them which are in Christ Jesus, who walk not after the flesh, but after the Spirit. - Romans 8:1
But the Comforter, [which is] the Holy Ghost, whom the Father will send in my name, he shall teach you all things, and bring all things to your remembrance, whatsoever I have said unto you. - John 14:26
Which things also we speak, not in the words which man's wisdom teacheth, but which the Holy Ghost teacheth; comparing spiritual things with spiritual. But the natural man receiveth not the things of the Spirit of God: for they are foolishness unto him: neither can he know [them], because they are spiritually discerned. - I Cor 2:13-14