

In general I get that and my instinct was similarly that it was strange not to use the word. I’d use Taoiseach for Varadkar in a way I wouldn’t use the native language word for other world leaders, because I think of Ireland as a primarily English-speaking country and that’s the word they still use whilst otherwise speaking in English.
But then again, I can also see that British readers like you and I who follow current affairs are going to be a lot more familiar with the term Taoiseach (or, in Calamity Truss’s case, the ‘Tea Sock’) given it’s the country next door and so hugely intertwined with British politics. I could name every Taoiseach in the last quarter century just by virtue of how much those individuals have featured in UK news - through the peace process, the financial crisis and then Brexit. I couldn’t do that for the leaders of any other foreign country of Ireland’s size. So I think it’s not unreasonable to assume the average US or other reader might not not know what a Taoiseach is.
I assume that’s the reaction they were going for by expressing the stat in that way, but aside from shock value it isn’t that informative.
Child mortality is usually expressed as ‘X per 1,000 live births’ so you have some sense of scale. We’ll never live in a world where zero children die before their 5th birthday (simply because of illnesses and accidents) but expressing the number of deaths per 1,000 gives you a sense of whether the number of deaths is a lot or not.
Here’s a UNICEF article that provides some more context on the 4.9 million global figure for under-5 deaths: ‘The global under-five mortality rate declined by 60 per cent, from 93 deaths per 1,000 live births in 1990 to 37 in 2022.’ To add more context on 37 per 1,000: in San Marino that figure is about 1.5, in the United Kingdom it’s about 4.1, whereas in several countries in sub-Saharan Africa it remains above 100 deaths per 1,000 live births - which I find to be a frankly much more informative and terrifying way of understanding the number.