It's the ousted leader of a country making a statement about his ousting. We don't treat state leaders' statements as "mere opinion" when they're televized, this isn't different. It's just not being contextualized by a third party so it doesn't go in the News section.

I could have posted the BBC article, but all it does is quote the op-ed and add a little bit of context. Since the release of the op-ed itself is newsworthy I thought it would be better to link it directly.

It was written by the President himself, this isn't some fluff opinion piece.