Dirty Dog is Butch the Bully
There is a popular theory that Dirty Dog is Butch after the latter grew up and became a furry.- Namely, he refers to Cool Cat's friends as being "rat haired", the same exact words Butch the Bully used in the previous film.
Corona-Chan is the Greater-Scope Villain in this movie.
Dirty Dog is a teen.
The only way he can hate both kids and adults without being a Boomerang Bigot.