I explained my Scriptural logic. You have not explained your reasoning from Scripture, apart from quoting a professor, who I have answered from Scripture.
If theological error is sin, then we are all sinners, especially as living our theology is a tremendous challenge. As John wrote:
1 John 8 If we say that we have no sin, we deceive ourselves, and the truth is not in us. 9 If we confess our sins, he is faithful and just to forgive us our sins, and to cleanse us from all unrighteousness. 10 If we say that we have not sinned, we make him a liar, and his word is not in us.
But, as we are forgiven sinners, we are righteous, not walking in darkness -
5 This then is the message which we have heard of him, and declare unto you, that God is light, and in him is no darkness at all. 6 If we say that we have fellowship with him, and walk in darkness, we lie, and do not the truth: 7 but if we walk in the light, as he is in the light, we have fellowship one with another, and the blood of Jesus Christ his Son cleanseth us from all sin.
You disagree with me, & vice versa but that does not mean either of us is walking in darkness, sinning by our theology.
I suggest that could be a whole new topic for contributors to disagree about.
You consider supercessionism to be incorrect, even sin. What precisely do you mean by supercessionism? I've looked at several definitions, but as it seems to be a term defined by those who reject what they define, I would not claim to hold a theology defined by others.
The Gospel of salvation through repentance & faith in our LORD Jesus Christ must be fundamental to all true theology. The interpretation of prophecy with regard to "end times" (this thread) is not necessarily fundamental,
BUT
when the focus is on the unregenerate, Christ-rejecting nation of Israel being God's chosen people, then it is a fundamental error. A member of the church I am attending made it a point at our first meeting, to the effect that the Jews have God's authority to expel the Palestinian people & take over their land & resources. That is in rejection of prophecy -
Eze. 47:22 And it shall come to pass, that ye shall divide it by lot for an inheritance unto you, and to the strangers that sojourn among you, which shall beget children among you: and they shall be unto you as born in the country among the children of Israel; they shall have inheritance with you among the tribes of Israel. 23 And it shall come to pass, that in what tribe the stranger sojourneth, there shall ye give him his inheritance, saith the Lord God.
And Jesus declared -
John 10:14 I am the good shepherd, and know my sheep, and am known of mine. 15 As the Father knoweth me, even so know I the Father: and I lay down my life for the sheep. 16 And other sheep I have, which are not of this fold: them also I must bring, and they shall hear my voice; and there shall be one fold, and one shepherd.
....
24 Then came the Jews round about him, and said unto him, How long dost thou make us to doubt? If thou be the Christ, tell us plainly. 25 Jesus answered them, I told you, and ye believed not: the works that I do in my Father’s name, they bear witness of me. 26 But ye believe not, because ye are not of my sheep, as I said unto you. 27 My sheep hear my voice, and I know them, and they follow me: 28 and I give unto them eternal life;