I mean, different kinds of rice do have clearly different textures, and basmati and jasmine are both aromatic in a way that koshikihari is not. I think people should be able to tell them apart easily (including just from "how easy is this to eat with chopsticks? could I imagine clumping this into the base of nigiri sushi? could I imagine this in a biryani?") but I think that's very different from deciding that one is better. To me your statement is like saying people cannot tell the difference a French baguette, focaccia and Japanese milk bread because "it's just bread". I think you wouldn't confuse them unless you were really distracted.
I agree with you and can tell, but I doubt most people around me could. They could understand each type of rice is different but wouldn't have a clue which is which.
It was a bit of hyperbole, but I think you'd be surprised how undifferentiated people's pallets can be if they aren't eating something constantly.