Most East Africans hadn’t realised that there are many Rwandans in Zambia, until last week, when mobs went on a looting rampage targeting Rwandan shopkeepers in the west of the capital, Lusaka. They were claiming that the shopkeepers were behind recent ritual killings in the city.

Now there is always a pattern to these things. The riots were really not about the ritual killings. It was about trade rivalry, and the economic crisis in Zambia.

As happened in South Africa last year, the local folks are not willing to accept that the success of the Rwandans is down to good business sense and hard work.

Rather, it is because they are chopping off Zambians’ body parts and using them to generate supernatural economic powers to outcompete locals.

Unsurprisingly, a day later the riots started to spread, and this time Zambian-owned shops were also looted.

In South Africa last year, Somalis and Ethiopians were the target. One minister even accused of them “hoarding their business secrets,” and refusing to share them with South Africans.

These attacks are a result of economic crisis. When everyone is doing well, and has a full stomach and food in the fridge at home, they will not seize on the slightest excuse to loot groceries.

The secret of why emigrants succeed is as old as the hills. Isolated away from home, and not being able to tap into local social security support systems, they have to work the shirts off their backs if they are to live. And being outsiders, they bring a fresh eye, able to see opportunities that familiarity has blinded the “natives” to.

As if to prove this, it is noteworthy that Rwandans were attacked for outdoing Zambians in business because, let us face it, in the world of East African stereotypes, when most people talk of business-minded people, they think of Somalis first, Kenyans second, and Ugandans third.

Rwandans are rather associated with bureaucratic competence and structure, the way Somalis are often associated with the lack of it.

Rwandans, to borrow from the language of motorsport, don’t make the front row of the grid.

Still, the hardworking migrant story is not enough to explain this.

A better path to understanding is to ask whether there is a country in the East African Community, where these kinds of economic-fuelled xenophobic attacks would happen.

While strong anti-foreigner sentiment often bubbles up in the region, my sense is that it hasn’t happened yet because of how business growth has happened in East Africa over the past 20 years.

Two decades ago, the East African countries had nothing. During Ujaama, Tanzanians were equal in having little; Daniel arap Moi wrecked Kenya’s economy; years of conflict and repression ruined Uganda; the genocide threw Rwanda back almost to the Stone Age; and conflict still has Burundi and South Sudan trapped in the Middle Ages.

In the economic boom the region has seen, everyone started from scratch, after most historical advantages were wiped out by political calamities.

There were hardly any newcomers who came in and overtook established business incumbents. Because no one was overtaken, as happened in peaceful countries like Zambia, and prosperous South Africa, there is less resentment.

East Africa is reaping some of the sour-sweet benefits of old conflicts and social and economic collapse.

Charles Onyango-Obbo is editor of Mail & Guardian Africa (mgafrica.com). Twitter@cobbo3