Did you have a point besides demonstrating that Plato obviously wasn't a biologist?
Not much, except that some creationists aren't either. Once one gets into the taxonomy, one finds that classifying groups by common ancestry is easiest and most practical. This type of classification is useful for agriculture, medicine, etc. Creationist classifications (or Plato's) aren't very useful.
Note that Linnaeus's scheme (even though done earlier) ends up being, for the most part, a common ancestry scheme. Linnaeus did common features but ended up with common ancestry.
Aristotle did make a classification of edible vs non-edible; it's also useful, if a bit crude.