If you wish to use "habitat" with humans, you can only do so when you are talking about environmental studies.
1. Towns and cities are man-made habitats for humans.
2. Caves with nearby sources of water were man's natural habitat.
One can, exceptionally, use it thus by extension as a metaphor:
Oxford with its dreamy spires, bright young men and gossipy academics is Professor Bachelor's natural habitat.
This means that Oxford suits him so much that it was as if he was a biological species created by nature uniquely to survive and prosper there.