Apple is claiming to have a visual equivalent to a cryptographic hash -- one which won't change with a single byte, but only if the image is substantially different.

At least their security analysis relies on that.

From their whitepaper: "The threshold is selected to provide an extremely low (1 in 1 trillion) probability of incorrectly flagging a given account"

If your claim is that their hash algorithm isn't cryptographic, their security analysis is incorrect.

It's trivial to cause a neural hash non-match-- either imperceptibly with a little noise, or by adding an overlay on the image.

If you downsample and quantize an image before sha256ing it you get a bit of robustness to accidental false-negatives. While both schemes are trivially bypassable.