I really don’t think he gets it....

My son is 10 years old. His dad has always been immature and has been calling our son fat and ugly since he was like 2. It’s always said in a very joking manner and he does the same with his friends and other family but.....it just bugs me to my soul that he does this with a child. My son has learned to joke back and call him ugly back but I know it still really bothers him. He’s internalizing it which I hate to see. And yes, I have mentioned it many times before but I always get told to “stop babying him” or “he knows I’m joking”. I hate it. And based on his response this time, I don’t think he’ll ever really understand. Am I making a big deal over nothing?