This is probably due to the ancient Arab influence and interaction (trade ties mainly but not only) with Kerala and Goa that are millennia old. Later Portuguese (who themselves were greatly influenced by Arabs after 800 years of Arab Moorish rule in Al-Andalus) arrived and others. All meat eaters.
Another clear reason is religion. Muslims and Christians eat beef. A third could be Arab tourists. I hear that a lot of Arab restaurants have sprung up in Kerala. A fourth the influence of communism and secularism in Kerala and in general that part of India being arguably the most developed part of India like most of South India is.
https://en.wikipedia.org/wiki/Mappila
I hear that even the famous Saudi Arabian dish Kabsa has become popular in Kerala, lol.
People from the Arab world, in particular Arabia, have good and friendly historical ties to much of India and in particular this part of India and vice versa. We look forward to enhancing peaceful and mutual ties with ordinary people. I know several people from Kerala and Southern India (Hyderabad etc.) and we get along very well. I have also noticed many similarities in cuisine that Arabia and India share. Greetings from across the Arabian Sea.