The joke was that she looks like Zira from The Planet of the Apes...
...who was not actual ape. The person she was referring to is not an actual black person.
Therefore it was never racist but a random comment made on another person's looks, a person who actually resembles in full-detail Zira from The Planet of the Apes.
People have been mentioning other people's looks since the beginning of time, it's not a crime.