This Gnostic excuse is meaningless
John said a child born of God can not live in sin, BECAUSE he has been born of God (he gives the reason, He has been born empowered by God)
People who deny the power of being born of God, then blast people who not only understand it, But have experienced it, and seen it, as gnostics well,, thats just wrong
I think you have missed the point being made. People can continue to sin in action, but claim they are pure and holy because their flesh sins but their spirit does not. This is the core of the gnostic position.
If you are saying through the power of God, you can walk in love and righteousness, Amen.
But I am not sure this is what you are saying, but it is up to you to clarify it, if you so desire.
If one actually holds a gnostic view, often the denial is a change of reference and language to try and make the accuser into an evil sinner who wants to appear good and following God but is not. It is because there is no gnostic view, only the elect with their perfect spirit and fallen flesh, and those not with a perfect spirit who mock its reality. The notion that there could be believers in the flesh who walk with Jesus is so alien, it cannot be accepted that anyone actually believes this, it is so bad, in their eyes, to even suggest such a thing is possible. God bless you