If I contrasted super-wealthy-nations with African nations, would this be hurtful towards Africans or is it just a reflection of economic statistics?
In fact, it is both. Even if we can agree that African countries are on the whole poorer than those on other continents, it is not typically such facts that cause offence, no matter how ugly or inconvenient they are.
What is hurtful is the gratuitous use of a racial/national stereotype to enforce a negative association.
African nations did not have to be singled out to make the point. There are many other countries struggling with poverty. And it was more accurate for me to say something like "low-income-nations". Yet I chose to single out Africans for the association with poverty rather than use a more general term.
This is what many people find insulting about such use of stereotypes.