The article doesn't justify the title. As far as I am aware, while Europeans knew the earth was spherical since the classical period, Chinese didn't.
The article is strictly limited to Europeans in the middle ages, not "everybody ever".
The article goes into other cultures briefly. It doesn't focus on those because it took longer to discover the roundness of the Earth there. This article is focused on first discovery, and the myths about the myth (like Columbus trying to provide the roundness of Earth). This article also doesn't well cover that the Bible texts refer to the Earth in terms of being flat dozens of times.