Even when you get kills.
Yup, I completely disabled my Outposts while I was grinding to Master.
The Rank system in this game is busted. Subtracting Rank points for any reason discourages playing. The other day, I built a new Outpost, a small Normal level, and it got some kills but apparently not enough: while I was raiding, after completing a raid on the first try, I saw "-214" rank points, and I deactivated the Outpost and stripped it. Haven't built a new one since.