You've named it: "tens of thousands of cases outside of Africa". It entered the white world (disclaimer: I'm white myself).
On top of that we've just lived through (hopefully) the worst if the COVID pandemic, so WHO is additionally spooked.
And apparently this decision was actually an overrule by the director - a panel actually voted against it.
> Monkeypox is a disease of global public health importance as it not only affects countries in west and central Africa, but the rest of the world. In 2003, the first monkeypox outbreak outside of Africa was in the United States of America and was linked to contact with infected pet prairie dogs. These pets had been housed with Gambian pouched rats and dormice that had been imported into the country from Ghana. This outbreak led to over 70 cases of monkeypox in the U.S. Monkeypox has also been reported in travelers from Nigeria to Israel in September 2018, to the United Kingdom in September 2018, December 2019, May 2021 and May 2022, to Singapore in May 2019, and to the United States of America in July and November 2021. In May 2022, multiple cases of monkeypox were identified in several non-endemic countries.
[0] https://www.who.int/news-room/fact-sheets/detail/monkeypox
This is as good a reason as any.
But that's not news. That's well known. Also, generalising 'news' makes no sense. Of course news sources from certain countries will focus on news that effects their readers. Deaths from diarrhea are of little relevance to the readers of any 'western' news source.
You’re probably being downvoted for this though it’s completely true.