Gee, it must've slipped their minds.
The media conveniently left this part out:
“The truth is that my health has been affected by long covid and this has limited my strength to undertake the breadth of travel essential to my position. Because I cannot be sure to regain that strength fully, I need to step aside for someone to be selected and to take over.” (from his email to staff)
Long Covid Forces The UN's Humanitarian Chief To Quit
https://www.donotpanic.news/p/long-covid-forces-the-uns-humanitarian
Long Covid Forces The UN's Humanitarian Chief To Quit
Martin Griffiths, the UN’s under-secretary general for humanitarian affairs, is quitting because of long covid. Although if you only glanced at the headlines about this news, you wouldn’t know it. Almost all of them told us that his decision was due to ‘health reasons.’