I'm not going to defend Japan. As I said I'm happy to believe they treat women worse than Saudi Arabia; which is what my source provided.
As for Rwanda, this is just plain absurd. This is at best a checkbox study where they are looking to confirm reverse sexism. Yes I did read Rwanda has significant reverse sexism. After the genocide their society was over 70% women and they elected leaders to provide sexist policies.
Reverse sexism is not an ideal to be aiming toward.