The important part about the hackerfactor link is that the author claims he was able to reverse PhotoDNA hashes into images. Of course Apple has their own, different perceptual hashing algorithm NeuralHash which they use, but if the hashes of a similar system can be reversed into images, maybe NeuralHash hashes can be reversed as well. Therein lies the problem.

Edit: i.e. OP isn't talking about MD5 hashes