I'm not entirely sure what the reference in John was actually about. I do know that if one confesses their sins contritely and ask Jesus for forgiveness His shed blood dying on the cross is sufficient for salvation leading to repentance by inviting the Holy Spirit to live in your heart to comfort and guide you in the life-long repentance process.
I'm not saying that you are wrong but it seems to me that your stance, without any clarification, appears to be an attempt to prove your perception of moral and spiritual superiority. Holier than thou types are generally not well received in the forums. That's just the way that it is. I'm not saying that you are a holier than thou type but that's the vibes that I'm getting.