People celebrating a murder are mentally ill weirdos. They don't represent secular society. The idea that anyone against murder must be religious is wrong. You

People celebrating a murder are mentally ill weirdos. They don't represent secular society. The idea that anyone against murder must be religious is wrong. You can ground "murder is wrong" in reason e.g. the golden rule, the categorical imperative, etc. Furthermore, it's not clear that a prohibition against murder started with religion.