I can't add a lot to it. I've studied a couple of recurrent zoonotic African diseases (Ebola and Lassa fever) but not monkeypox. Two things do come to mind. One is that diseases that were thought (by non-Africans, anyway) to be rare sometimes turn out mostly to have been overlooked. This is the case with Lassa, which was thought to be an exotic new disease but which turned out to be common in some parts of West Africa. The other is something noted in the article, which is that changes to the environment -- increased contact with wildlife, increased human density -- are amplifying the appearance and transmission of zoonotic diseases. So yes, they really are becoming more common. (That may be the case with Ebola -- it's not entirely clear.)
The nagging worry with a lot of these viruses, of course, is that they'll mutate (evolve) to become better at human-to-human transmission, something we've seen repeatedly with SARS-CoV-2. So, while I'm not (yet) too worried about this outbreak, I do have an underlying level of concern for the overall situation. Which is why we all should be pressing our governments to spend more on public health and on improved health care systems around the world. Not just because it helps relieve ongoing suffering of vulnerable people caused by disease, but to protect ourselves, too.