Ready for this to age poorly.
The higher the rank in general, the more they know. Akainu is privy to a lot more information than your typical marine, even just due to the circumstances of his job. He interacts with Gorosei and cd’s on a daily basis. He knows they’re up to all sorts of shady stuff. He surmised that there is a power higher than the Gorosei within the WG.
That said, my belief so far is that his understanding and the understanding of other high ranking marines like Garp and sengoku is that what they get up to is for the greater good. He killed the civilians in Ohara because he thought the product of their research would unleash weapons of mass destruction and throw the world into war. (Rightfully so)
The Gorosei seem to have stuck consistently to their story of void century research being prohibited chiefly to prevent the ancient weapons from being awakened. They stuck to that story literally till clover’s last breath. We as readers know that they’re hiding something much more sinister, and likely grave misdeeds by the 20 kings. And likely an intention to wipe out a significant amount of humanity.
But does Akainu know? Likely not at the moment, but he’s increasingly showing signs of piecing more together. Additionally, since even Vegapunk and Rayleigh seem to think there’s grey area in who was right and who was wrong, you can bet that the Gorosei have painted a picture to high ranking marines and even other celestial dragons (saint shalria doesn’t even seem aware of the void century altogether) that makes the WG appear to have pure intentions, and any of their opposition, past and present, being evil.
