They aren't insulting another ethnicity's cuisine, they are criticizing the quality of the meat that an eatery serves when it ostensibly is serving that cuisine. Notice here how a parallel thread here is all about how to find better-quality kebab than elephant's leg, so people obviously want the ethnicity's cuisine. (And as someone from the European continent, I have heard "elephant's leg" locally, it is not just a Brit thing.)

Nevermind that across Europe, the workers hired to run elephant-leg döner joints for absentee owners are from the Indian Subcontinent. It is not even their own ethnicity's cuisine, it's just the work they could get.

Again, your failure to understand these basic facts and propensity to misinterpreting your interlocutors is baffling.