My opinion is it is misinformation. The cases only involve people living in, or going back to Japan when divorced. In fact saying Japanese marrying foreigners already shows bias, If the divorce happens in another country then the Japanese person is the foreigner for example and almost all of the problems listed in the article could only happen if the couple were living in Japan at the time. For example in the US a child can't even move to a different city without permission much less leave the country. So the answer is simple, you have a kid leave Japan even if it is just for the divorce, problem solved.