* Xandar and the Kree have just finished a brutal interstellar war.

* Thanos is literally insane and he wants to commit genocide on a galactic scale to impress Death herself.

* Peter Quill was kidnapped, grew up without parents and was forced into a life of crime, all the while the death of his mother traumatized him his whole life.
Gamora and Nebula were taught to fight each other from childhood on.
Rocket Racoon was experimented on.
Drax lost his family and went insane.
The Collector is almost as old as the universe, the last of his kind, and insane.

* Ronan attacks Xandar and hundreds of fighter-pilots die und uncounted civilians die.

* Xandar puts the MacGuffin in one of their vaults, setting the stateg for the next-best cosmic war, because their planet and their civilians are now a prime target for any galactic superpower who wants that thing.





And how many people were killed by Ego? Let's not even get into how many of his wives and children he killed.

And Adam Warlock (from the post-credits-scene in GoG2)? In the comics he's a superwarrior who kills people and who's then constantly tormented by the fact that he killed somebody. Oh, and a future version of himself turns into an insane dictator.

The charge is never denied nor disproven, either. Heck, by part deux it's entirely forgotten. Convenient!