Just as the existence of America as we know it necessitates the pillaging and raping of native tribes. But we're not going to watch over your shoulder to make sure you don't participate in American society and send you to jail if you do. As unfortunate as past damage is, life moves on.
Of course, that it incentivizes production of more CSAM is the logic behind the laws, and that is a pretty compelling reason. However, according to the continuous stream of news reports, a tremendous amount of content has already been produced. How much more content would need to be produced? If the adult porn industry stopped producing new content, nobody would ever really notice. Algorithms do incentivize production of more and more adult porn even as 90% of will never been seen by anyone, for sure, but the law could still take a harder stance on those algorithms if that is the better solution.