You are absolutely right.
Huck Finn is one of the most powerful anti-racism statements ever written.
I found the end, where Huck decides to help Jim escape and just accepts this means he will go to hell, profoundly moving.
Particularly when you remember the author was raised to believe exactly the same thing and had obviously rejected it.
Those who cannot see this and instead fixate on the use of particular words are idiots.
Do you think that since he really believed it, he went to hell?