What's shocking to me is how little Apple management understood of what their actions looked like. Really stunning. For a company that marketed itself as one of the few digital service providers that consumers could trust, I just don't understand how they acted this way at all. Either there will be heads rolling at management, or Apple takes a permanent hit to consumer trust.
Why are hash collisions relevent? There are atleast 2-3 further checks to account for this.
Because it's not a cryptographic hash where a one bit difference results in a completely different hash. It's a perceptual hash that operates on a smaller bitmap derived from the image so it's plausible that some innocuous images might result in similar derivations; and there might be intentionally crafted innocently-looking images that result in an offensive derivative.
Salvador Dali could do something similar by hand in 1973 in Gala Contemplating the Mediterranean Sea [1]