I don't know whether you are just arguing to argue. You should stop misrepresenting my position (although this is forgivable if you sincerely misunderstand it). My position is this.
1. Marriage practices must be judged within the specific cultural context where they occur. Cultures don't even agree on the meaning of "child" or on the meaning of "marriage". What is wrong in one culture is acceptable in another culture.
2. In cultures like the Yanomami, for example, I believe that child marriage is acceptable as it is practiced within their society. Again, the definition of "child" and "marriage" as they understand them are different then your understanding, as is the meaning of these practices. It is invalid to judge the effects in one culture from the values of another. Reading the reports from anthropologists, it is difficult to see objective harm in the practice.
3. As the only person questioning the simplistic Eurocentric view, it is difficult for me to expressing the ambivalence that I feel on some parts of this issue. I have no trouble expressing this... except that everyone here seems to be taking the position that the Western view of marriage is the only acceptable view.
4. That being said, I do think that Western cultures should mostly butt out from indigenous cultures. It would be a crime against humanity for us to interfere in the Yanomami culture even to stop the child marriage happening there (and fortunately it is protected). We have done this so many times in the past.
5. The difficult political considerations involved countries that Europe has already screwed over. I suspect that Middle-Eastern cultures had functioning family systems.. much of the worst dysfunction is because of Western colonialism.
Anthropologists say that there are functioning, societies that provide full lives for men and women that include "child marriage" (however child marriage is defined). This may be difficult for someone indoctrinated in Western culture to accept... but by any objective measure it seems to be true.
6. I do believe there there is a prevalent sense of Western Superiority in liberal thinking that makes multiculturalism impossible to accept.