It included the religions of the major countries of the world, but it must still face some philosophical. While universality was shown quite well, one of the conclusions is that we do need to look more carefully at the scope and meaning of the word love in different cultures. However, this applies to all words and the vocabulary that is used. For example do we use autonomy for individuals, for families, groups, city-states, or countries. Justice can be also applied in numerous ways.
All words have linguistic ambiguity.
I actually think some reject love because it is just too simple to understand. The challenge is for us to do what has been talked about around the globe throughout human history. We can see examples of this conflict in local debates, for example Buddhism and Hindi rituals, Mo Tzu with universal love and Confucius with emphasis on family duties, and Christian love of neighbour as a response to Jewish legalism. Importantly, we can also see this tension within each of those schools of thought, and probably across all cultures of the world. It is a question for on-going research.