Which is why an overly harsh approach is self defeating. Anyone can thump their chest and say “don’t do it” if they’ve never been there and wrangled with the devil about it, seized hold of Christ’s power and won, and can describe what happened.
No need for the "walk a mile in my shoes..., etc."
God does indeed call some to be his messengers, to point the way to salvation, lest they (the lost or wavering) be forever lost but people today, just as in the Old Testament, hate the strong light of the truth, stone and even kill His messengers and refuse to listen to His messages.
Jesus reminded the religious leaders of His day that they killed the prophets sent to tell (some might say "preach") God's warnings to His people.
People need not be perfect to speak of God's laws to people, or even to have been tempted by a specific sin, to warn others of the unchanging nature of God's hated of sin.