I just watched the vid and there are a number of underrage girls that participate in that ceremony which is uncomfortable. Also, the fact that a quarter of their population has HIV is also disturbing. But I'm a westerner so within our framework, pedophilia is wrong. However, as a westerner I don't think it is right to judge a culture by our standards. Culturally, it appears that their people are fine with it as it has obviously been a tradition that has been happening for hundreds of years. And I am not one to say that our thinking is better than other people's thinking.
My ex girlfriend, who is a descendant of Shaka Zulu, works for JP Morgan in IB. She's very modern and forward thinking and a bit feminist. She told me that during traditional ceremonies, the women of her tribe go topless. So you have all these accomplished women - doctors, lawyers, etc.. that are topless at these ceremonies and they have no problem with it because it's tradition, it's part of their culture. So I can't judge.
What I will say is that Mswati could have used better judgement knowing modern day thinking on the treatment of young girls and so really is at fault for any backlash he may receive.