Editing Spawn Mechanics (section)

=== Eliminating Outposts/Bug Nests ===
Destruction of up to 50% of outposts on the battlefield results in no change in the battlefield constant. Once you surpass 50%, each additional outpost destroyed will lower the threshold needed for a spawn. This is a linear formula that when all outposts are destroyed  the Threshold is multiplied by 0.85 resulting in approximately at 17.5% decrease in spawn time. So if there are 8 outposts - and it doesn't matter if light, medium, or heavy - you are able to destroy 4 of them without any effect.

This actually creates a unique interaction on the battlefield constant. So yes, eliminating these outposts does actually add more enemies eventually. But!!! In exchange you eliminate their area of influence. What this means is that you no longer generate heat nearby their location. This is very important to consider when looking at traveling lanes, points of interest, and completing objectives. It very well may be that the heat being in close proximity to the location is more of a threat than elimination of the outpost.