Yes he does forgive the individual who repents, as did King Manassah who started the practice but God did NOT forgive the nation of Judah. He warned them before they went into the Promised Land. They were given the land because the natives were practicing child sacrifice, not because they were better than the natives. He said if you do this, you will be invaded. Is America being invaded? Did any nations in South America practice human sacrifice? The American natives were said to do so also, but no one talks about it.
But did not when a nation repents God backs away from the punishment?