I could be quite ignorant here but considering the start of this a while ago was the fear that Apple would scan your entire photo library without consent, I feel like this is fair trade. It makes sense that the quite literal public link, open to anyone, is also accessible to Apple. Also makes sense that with this public link directly connected to Apple, they want to ensure that they arent complicit in anything illegal or harmful. I would be curious what their actual definition of "harmful" is though.
I also appreciate that they explicitly mark out the difference between sharing with "People you choose" and "Anyone with link". I'd love to hear other people's thoughts, I know the opinions on Apple are very diverse lmao