Instinctively I am with your line of thought, although I understand the other point of view.
Here, Our Lord's dealings with the woman taken in adultery seem highly relevant.
To prove adultery in Jewish law was difficult; either confession or being caught in flagrante were necessary. In St. John's Gospel we have the latter. The penalty of the law was quite clear - she should be stoned to death.
This, of course, is why the Pharisees presented it to the Lord. He'd being going round preaching forgveness, so either He had to do that here - and be called a law-breaker; or He had to do what the Law of Moses demanded, in which case where was all that forgiveness stuff then?
Of course, being the Lord, He found God's way. When no one there was without sin and therefore able to condemn, neither did He. But He didn't just say, 'Have a nice day', He told her, as He tells us, to sin no more.
We are called to repentance - and forgiveness.
In this is love, not that we loved God, but that He loved us and sent His Son to be the propitiation for our sins. (1 John 4:10)