No, Malayalis are not forced to eat beef. I don’t eat beef. I have never eaten it and don’t think I will ever too. That said, I don’t have any issue with others eating any food of their choice.
Many people who have answered this question seem to have gone to the extreme of glorifying beef and generalizing malayali taste. Beef is not an emotion in Kerala, contrary to what many people seem to imply. It has been politicized very much these days which is why you see many emotional beef lovers going on to write passionate answers. Because of this poloticisation itself, it has made its way into many movies and contemporary art. It is only natural.
The most sold meat in Kerala is not beef, but chicken. Going by the statistics released by the Animal Husbandry department it occupies 45% of the meat consumed in Kerala. Therefore, if any meat based food should be considered an emotion, it should be poultry meat.
Coming back to the question, many malayalis believe that matters like food, dress etc should be left to individual choices. Therefore there is not much opposition from people who don’t eat beef to those who eat it. There are exceptions to this culture of tolerance creeping up these days of which only beef seems to get widepread attention.
For example, many people from a particular community attacked actor Asif Ali online for posting a picture of his wife without a hijab on facebook. There is growing intolerance in our country and that is reflected in Kerala too. These are not confined to any particular community/caste/religion. Of these only some issues get attention, which is why notions like what is reflected in the question spread.