According to David Olusoga and Casper W. Erichsen, in their book The Kaiser's Holocaust (London: Faber & Faber 2010), the Rehoboth Basters were forced to fight with the Germans against the Herero under the terms of the treaty they had signed with the former when the colony was established, but refused to wage war against the Nama, who were led by a charismatic and capable leader called Hendrik Witbooi.
Witbooi, say Olusoga and Erichsen, in spite of having heard about the atrocities committed by the Germans against the Herero, chose to play by "the rules and conventions that were a central part of Nama tradition."
The Herero had also played by the rules and didn't target civilians, yet the Germans treated both them and Nama as decades later they would treat the Jews and the Slavs.
As for more recent history, according to this 1998 article published in The Independent, in the years previous to the independence of Nambia, at least some Basters engaged "in an ugly ideological marriage with South African apartheid."
I don't know how this community deals nowadays with its fraught past, and if they remember at all that before trekking to Namibia in 1868 they had participated in genocidal campaigns against the /xam Bushmen of the Karoo.
JE comments: I read The Kaiser's Holocaust some years ago, at José Manuel de Prada's recommendation. The historical record often paints Imperial German colonization as (slightly) more benign than that of the French, Belgians and even the British, but this was not the case in the nasty, genocidal campaigns the Germans waged in Namibia.