Comment by Terr_

> Waging biological warfare on the critters is not what I thought I was signing up for.

Alternate framing: A grey-goo apocalypse caused nanobots to consume and occupy all the convenient parts of the planet, and after billions of years of assimilation and hacking, some of the survivors formed a mobile hivemind megafortress which can "garden" and feel conflicted about it. :p

In other words, it's biological warfare all the way down.