In another example, does anyone really believe this mayor is so clueless to think what he's saying isn't racist?
Yep.
Now, that lack of self-knowledge alone is enough for people to want him out of office, but it is a fairly common occurrence - a person having biases that he or she doesn't know they have. He probably thought, "I don't like him, so I'll insult him," That, in and of itself, isn't racist. Even comparing politicians to animals is not itself racist - how many political cartoons have depicted politicians as pigs, for example?
But, it seems to me very likely that the exact form of insult came from a racial bias that he doesn't realize he has.
And, if he doesn't realize he has it, when confronted angrily on it, human nature makes it very, very likely that he'll dig in, and outright honestly believe that it wasn't racism that influenced his words.