Plus a highly contagious virus transmitting quickly through a close knit immigrant community should be unsurprising to anyone with any idea about epidemiology.

This article (about the Assyrian-Syriac immigrants, who aren't as dark skinned as Somali, but are also hard hit) explains how they come into contact with a lot more sick people and thus transmit it:

Earlier this month, the country’s public health agency reported that people in Sweden with foreign backgrounds are disproportionately represented among those who need hospitalization.

That squares with the experience of Terez Kino, a resident of the city of Södertälje and member of its large population of Assyrian-Syriacs, an ethnic minority scattered across Turkey, Syria, and Iraq. She used to have five carers, all of immigrant background as well, who would come to her home and tend to her needs. Four are now sick at home with virus symptoms. Her elderly sister has also contracted the virus from her carers, and her brother recently died of the virus. Her son is now taking care of her.

https://www.csmonitor.com/World/Europe/2020/0427/With-scienc...