There are two readings to Helldivers lore. Either the evil fascist government is farming the bugs and allowing the robots to keep making more robots as some sort of control mechanism and external enemy to fight, or the fascist government is so incompetent that all it's effort is misdirected at ineffectual efforts.

I lean towards the latter because all we do as divers is throw grenades down bug tunnel entrances and into robot fabricators. The bugs clearly have vast subterrean hives that we never see, we just kill the symptom on the surface with 500kg bombs and mini nukes. We probably never fully defeat the bugs on a given planet, we merely cull them enough so that they retreat from the surface for a time. As for the robots: their technology is on par with humanity and they might simply have different FTL technologies. If they want to lay low, they absolutely can.

So yea, fascists be incompetent and wasteful. They fly oil into orbit from a planets surface via rocket ospreys, clearly their methods are crap!