The article mentions a land dispute. Kenya has a murder for land problem.

It takes many forms, including witch hunting - the spread of witch hunting in sub Saharan Africa mostly an excuse for land grabs against the weak. Old man, single women, get targeted by gangs under the guise of witch hunting. It is also fueled by Christian churches vying for power against traditional religion in the region.

Sorry, went off track a bit. But even though it was her ex who did it, it is very likely a land dispute rather than misogyny behind the horrid crime.