OK I understand your point better. You are correct in that the thief on the cross did not yet understand doctrine but he believed the truth that Jesus was Lord, and that his faith was counted as righteousness. However, it is also clear in Scripture that saving faith is always accordant with who Jesus is, the eternal Son and not a created being. Jesus Himself said, “Unless you believe that I am He, you will die in your sins” ~John 8: 24 and John wrote, “Whoever denies the Son does not have the Father” ~1 John 2:23.
I agree that new believers have to start with the basics, but it is also clear as we grow we must know the true Christ revealed in the Word. “Grow in the grace and knowledge of our Lord and Savior Jesus Christ” ~2 Peter 3:18. And while faith must start simple, it must be rooted in truth or it is not the faith the Scripture describes. That is why I say this isn’t about labeling anyone, it is about protecting the purity of the gospel.