First that article hardly makes it clear that that was the US's bomb. Second it was 25 years ago. Third, you do have a black and white world view? And all countries are clearly equal?
Are you seriously unable to distinguish between countries? Are you unable to distinguish between single (or even rare) occurrences and repeated? Between countries that feel bad about such occurrences in their past and those that celebrate them?
Do you really think that saying "So and so is not so bad - after all the US did it one time." is a good argument?