Morality is most definitely subjective. Talk to different groups around the globe and you’ll find different moral boundaries. The morals posed by Islam differ from christianity, which differ from buddhism, which all differ from nihilistic views, and still further diverge from tribal morals of small secluded tribes of people. While they shouldn’t be based on emotion, they do tend to be reactionary and emotional at their outset. And breaking them within any particular group tends to get you strong emotional responses.