Their representation was consistent for one thing. For another it was well known that a) the world isn't black and white and b) b&w is just the tech we have right now. For a third thing, once color came out, black and white was still popular because it was a known art form that exposed characteristics of a scene which a color photograph might miss. So it was fudging images in a way that was predictable.
Compare this to AI/ML-manipulated photos that aren't labelled as such. In this case we no longer know if it's our brain fudging a picture or our camera, so we are starting to lose an arbiter of truth.
Side-rant but it'll be weird when this makes it into high-end cameras that save RAW images. Will RAW still be "raw?" I don't know enough to say.
