I think just about every country east of the Iron Curtin would disagree with you. If you don't believe there's serious issues in Europe, especially Eastern Europe, you are mistaken.
You are right that to compare South Africa to, say, the Sudan is a gross simplification, but to compare Slovakia, Albania or Kosovo to France or England is also unfair.
Right, I'm with you. When we talk about Europe as colonists we're not talking about Albania and Slovakia. Albania was an Italian colony, right? We mainly mean England/France/Spain/Portugal/Italy/etc.
A lot of those in Eastern Europe probably wouldn't be considered European to many in the west of Europe, which is also part of the problem.
I think that's what people are trying to tell you. You say "Europe" like it's a thing. A monolithic entity that needs to address the complex problems that exist in Africa. But Europe is not a thing. It's has a complex set of its own problems. Gates is using "Africa" as a shorthand for the same reasons you used "Europe" as a shorthand, because it makes it easier to
1. Deliver the message quickly and clearly and
2. Bring people to the discussion who don't or can't have a complexed or nuanced view of the problem, but would like to do something to help.
I, for example, may have money to donate or some skill to assist, but I don't really want to commit myself to understanding "Africa". I'd rather leave that in the hands of someone who does understand it. That's what people who try to gain the limited attention of the public do, oversimplify. And regardless of what the public says, they want that simplification. My head would spin if I had to know every nuance of every specialty just to make a decision.
Also, Italy was hardly a colonial power in Africa, but Belgium was. So we're back to sum up a difficult history to a way people can wrap their heads around it enough to write a check.
Gates used "Africa" as a shorthand next to "safari" and "wild animals", which unfortunately is what many people think when they think of "Africa". I have no problem with the word Africa, but I do have a problem when people use it and reinforce those stereotypes.
All I'm trying to do is point out that those notions are part of the problem.
You are right that to compare South Africa to, say, the Sudan is a gross simplification, but to compare Slovakia, Albania or Kosovo to France or England is also unfair.