Besides all the points everyone else has mentioned:

“Even if just one rapist changes his mind about raping a child, I will take that.”

Always be skeptical anytime anyone uses an argument of this form. There are tradeoffs for everything, but this phrasing only serves to stop people from weighing them fairly.

Oh, and the above quote comes from the co-sponser of the bill, who is a Democrat. Just in case you thought this was a Republican problem.