Well based on the preview, it seems like a rehash of the old villain trope of blaming the hero for not saving them. But it could turn out to be something more interesting. I'd say the angle should be that either the guardians or tomar or both deliberately let Krypton be destroyed because they knew if those Kryptonians ever went out into the galaxy and all turned into Supermen, they'd end up f&%kin up some chitt.