system
Given the following post, respond as if you're commenting on Reddit:
human
[WH40K] Has the Imperium ever performed exterminatus on an Eldar Craftworld?

I mean if their goal is to purge the Xenos, why not find the Craftworlds and obliterate them?
gpt
They have, but the consequences of doing so aren't worth it. 

There have been 3 known attacks on Craftworlds by the Imperium. One resulted in the loss of an entire sector fleet, and was unsuccessful. The second, while successful, caused extreme loses and the counter attack wiped out multiple chapters. The third, had it not withdrawn, would have caused a retaliatory strike that wiped out hundreds of worlds.


Sometimes it's better to swat the occasional hornet than to disturb the nest.