As to points made… yes, the Pirate’s superiority, and our superiority over other species, comes from our mastery of tools and technology. It’s why we’re the dominant species - physically, in comparison to a wild animal like a wolf, we are poorly equipped and very weak. However, we are smart, sentient, and sapient. We can make tools. A wolf can’t stand up against a gun unless it’s smart enough - and has the appendage structure - to make a gun itself.
Wolves WOULD be the dominant species, if they had gotten the cranial enlargements we evolved and became bipedal. The same can be said for any other creature, from a fox to a dolphin to an anteater. Instead, their survival continued to focus upon strength rather than smarts, and from that comes their lacking of tools, and therefore our superiority - because we’re smarter than them.
So anyway, our point is that the Pirates are just simply better equipped - they have better tools, better weapons that we can’t compare to. They’re genetically engineered and grown in vats, trained for pure efficiency with a variety of modern weapons and bioengineered armor.
In one-on-one combat, against a human soldier, a Pirate would win without any effort. Against a squad of them? Still no effort. Against a hundred thousand of them? Then, perhaps, it would be a challenge and the pirate would possibly die.
To defeat them… we’d need a hundred thousand crack troops per Pirate.
An invasion fleet would likely consist of hundreds of thousands of pirates in itself. Each one which is so vastly better equipped than our own soldier that it would take a huge amount of our own soldiers to beat just one.
I don’t need to tell you much past that, do I?
Nukes are useless because the Pirates have undoubtedly mastered point-defense technology that can destroy any slow projectile heading their way. Their carapace is obviously too hard for even futuristic small arms to penetrate. Even if a high-velocity sniper rifle bullet could pierce that exoskeleton? We still need hundreds of thousands of snipers each with the perfect location and the perfect shot every time. I don’t see anything working.
All in all? We don’t have a chance in hell. There’s simply nothing that will work… if Pirates went back in time and invaded earth at the present moment, there’s simply nothing we could do.