

That’s not a rule he can get rid of. The seal of confession is a matter of doctrine and divine law and the pope isn’t authorized to overrule god.
Also, again, there’s no rule against turning in child rapists. There’s a rule against breaking the seal of confession. If a priest finds out about a crime in any manner besides confession, they’re free to contact authorities.
And it’d be a dumbass idea anyway. If a criminal is coming to confession in the first place then there is some remorse for what they’ve done, which means that person might be encouraged to turn themselves in. If you started reporting them when they came to confession, it’ll work once or twice and then criminals would just stop going to confession. Which additionally, is an anonymous act. The priest doesn’t know who you are when you go to confession.
In many states priests are mandatory reporters.
But they can’t be forced to abandon their religious beliefs by the government by breaking the seal of confession.