It's not contradictory to simultaneously hold the positions that (1) porn consumption is bad for minors, and (2) adults who watch porn should not be forced to upload identity documents to insecure systems managed by unwilling operators.

And that's just assuming the law could even be perfectly enforced! In reality, it will not be, and there will always be sites without the requirement (which will also be the "seedier" sites), or kids who work around it. So the end result is that kids end up watching even worse porn, while adults get their identities stolen and linked to their porn browsing habits.