Being pretty late to the colony making party helps too. The other powers had already laid claim to the most valuable parts, so Germany grabbed what was left, leading to Deutsch-Südwestafrika.

Also as far as I know, in comparison to the other colonial powers they acted almost tolerable, I read an article some years ago that supposedly revealed a notable difference of opinion amongst the people on the former colonial powers, with the germans having a pretty good standing compared to the atrocities committed by places such as belgium for example.

That being said, being the least violently brutal and cruel of the oppressors is still being an oppressor. Just not the worst.