Both sides are definitely not right/wrong. Imu isn't even remotely morally ambigious, his plan this arc is centered around kidnapping children to make giants accept slavery.
Let's not even get into God Valley.
I'm talking about what started the conflict, it's not like those who oppose WG are all good guys, Pirates are scum, and all rebels have good intentions, we have Dalton, but also have Hody, so it doesn't matter how evil or how good each person on each side ended up becoming, the conflict itself had a trigger, and in that exact moment, we don't know who was right/wrong,
Skypieans & Shandians Fight started because of Jaya ending up in middle of Skypiea, you can't blame them both for fighting,
From Shandians Perspective, it's their Land & They must defend it, but from Skypieans Perspective, that Land is now inside their Kingdom & They can't just sleep at night trusting that those Shandian strangers won't harm or invade them, and neither of them planned such situation, it was all a Natural Disaster.
Even if one side is evil, it doesn't remove the existence of Third Faction of Outsiders who threaten both sides,
In Drum Island, King was Evil (Wapol) while Rebel was Good, but in Arabasta, both were Good, and In Fish-Men Island, the bad guy was the Rebel instead ... etc but at the end of the day, Drum Island was threatened by Blackbeard, Arabasta by Crocodile, Fish-Men Island by Big Mom and so on,
The Term "Pirate" can only refer to an Outside Threat, if you stay in your City & start ruining it, then you're just a National Criminal or Bandit or Rebel or Terrorist ... etc that's why Final Villain cannot be someone fighting for the Throne, it's a complete outsider to both sides who just wants to loot the place & pillage it, if They take the throne, that's just a temporary bonus for them.