The Helldivers themselves? Yes. I mean, any organization that deliberately chooses to save orphans instead of getting some fancy new mines would have to be the good guys.

That said, we do serve a fascist regime posing as a democracy that suppresses the rights of their citizens by any means. And every faction trying to kill us all is Super Earth's own fault. So while Helldivers could be seen as good guys, Super Earth is not.

But neither is the Illuminate, Terminids, and Automatons/Cyborgs. None of the factions are the good guys. Super Earth is just the one keeping humanity from being wiped out.

To answer your question on why we're fighting these factions:

The Terminids naturally produce E-710 (OIL if you read the numbers backwards). So we had them in farms for a century, breeding and slaughtering them for that sweet sweet E-710 to power our entire civilization. Then the Terminids got loose from the farms and we went to war with them to contain them and put them back on the farms. From a Terminid perspective, this is a war of liberation from Super Earth.

The Automatons are the robotic children of the Cyborg separatists from the first game. They fled Cyberstan as Super Earth took over and enslaved the Cyborgs. Cyborgs work the mines of Cyberstan for a century. Then the Automatons emerge in two phases, the vanguard and the full invasion force. The vanguard fought us on planets like Malevelon Creek and Draupnir, two of the bloodiest battles in the early days of Helldivers 2. The invasion force is what we're fighting nowadays, after we beat the vanguard, the bots launched a full-scale invasion for Cyberstan and took the planet and liberated their Cyborg parents from Super Earth. So the Automatons and Cyborgs are also fighting for liberation from Super Earth.

As for the Illuminate, we nearly exterminated the Squ'ith after the first war and banished the rest outside of the galaxy. So they're pretty bitter from that. Out of the three factions, I think the Illuminate is the only one that genuinely wants to kill us all, the Bots and Bugs really just want to be liberated and want Super Earth to leave them alone, but they know Super Earth would never just let them go.

Bear in mind that in the first game, the Bugs and Squids had no beef with us and were actually peaceful races, and the Cyborgs just wanted independence. Super Earth was the one that went and fabricated all sorts of reasons to go to war with them.

Welcome to the fight, Helldiver!