User blog comment:Reptileman778/What is the canon explanation for why you are fighting geth in multiplayer?/@comment-2186773-20120911183650

I think they said the more isolated geth weren't in the range of the sentience signal so they still worship reapers, and geth don't always die when you destroy their bodies, so like 100 geth can be fought a million times apiece as long as they keep building bodies, and then they can program more geth in any case.