It confuses man's responsibility with his ability, and falsely assumes that a sinner has the moral ability to perform all that God has commanded. The cannot texts of scripture are either totally ignored or badly twisted by this perversion of the true gospel of God's saving grace. Man cannot understand - until he first be given a new nature. Man cannot come - until he first be effectually called by the Holy Spirit. That something is what the Bible calls regeneration, or the new birth, and it is the exclusive work of God the Holy Spirit.
Man has no part whatever in regeneration.
When the Bible says man is dead in sin, it means that man's mind, heart, and will are all spiritually dead in sin. When the Bible speaks of our being in bondage to sin, it means that our entire being, including our will, is under the bondage and power of sin. We indeed need Christ to die and pay the penalty of our sin, but we just as desperately need the Holy Spirit to give us a new nature in regeneration. The Son of God frees us legally from the penalty of sin, but only the Holy Spirit can free us from the power and death of our depravity in sin. We need forgiveness in order to be saved, and Christ provides complete forgiveness and righteousness for us in His death.