Famously banned (one of the "Warner Bros. 11"), there doesn't seem to be a really pristine copy of this out there. I don't think the cartoon is very derogatory, nor do I think that banning it is productive. What should be banned is cops shooting innocent Black people and loading up our jails and prisons with Black people for insignificant reasons, then using the criminal records to deprive them of jobs and housing.
This IS racist, there's no question about that. Back then, painting black people as simplistic big-lipped stereotypes was accepted, but today it feels reactionary. However, censorship is not the answer. Coal Black is still technically excellent, and it's good for classroom discussions and analytical approaches, when there's proper background and talk about why this kind of goofy blackface stuff is wrong.