There’s nothing derogatory about “eaters of raw meat.” Just ask the Japanese — or me. I love to eat raw fish.
I would say that it depends upon the context.
If the person saying it has, in the past, made it abundantly clear that he despises meat-eaters and that he believes that eating raw foods is the epitome of barbarism, then it can be taken as an insult - even if the insulted person himself has no such qualms.
If you don't think so, try going to a predominantly Italian neighborhood in New York and loudly calling someone a "spaghetti" (short for "spaghetti-eater").
Regards,