Because if you group them together a posteriori it does not reflect the conditions that a single country has to fulfill in the Olympics. For example every country has a set number of athletes for each sport and each category of said sport that they can take. So in this situation the country "EU" was competing with much more participants than it would have been allowed if was a single entity.
Atomikfratwerk laughing at turkeys position in Olympic medal table
His country argentina literally chilling at the bottom in a comfortable #100 place: 👍🏿
BTW Europe with the 1st ever Olympic gold medals in history in climbing, karate (female and male) and probably baseball