Yes, using cryptographic hashes prevents them from fuzzy matching and the algorithms that allow for efficient matching and fuzzy matching require comparing the bare hashes.
This seems dumb. I'm sure that sophisticated bad people will just alter colors and things to defeat the hashes and meanwhile trolls will generate collisions to cause people to falsely be flagged.
The perceptual hashes are specifically designed to correlate images that are visually similar while not being exactly alike, even when the colors are altered. See:
