Humans typically aren’t considered “animals” even though we are. Probably because other than our brain size we’re remarkably mediocre or even bad compared to the rest of the animal kingdom.
It says "The World's Fastest ANIMALS", and Sonic is a hedgehog, and hedgehogs are animals. So, stop commenting on who's faster than Sonic, because it's irrelevant, and invalid. (Also, I got the speed of sound off of Google, so it's 100% correct.)