a: if the rights holders had wanted to they 100% had grounds to sue, and they would have probably won
b: the getter emperor is so cool! and someone should have told the people at gainax "if you're going to do getter emperor, the manifestation of colonialism and genocide as the natural extremes of directionless shonen hotblooded spirit and humanities endless potential for evolution, you need a stronger argument than "nuh uh" when saying 'actually this is a good thing. it's good to forever grow and become more powerful and kill everything in your way'"
if i ever rewatch it i'm not going to be able to see team gurren as anything other than evil. seeing kittan's sacrifice and shaking my head like "he succumbed to the corruption of the getter. sad!"
or maybe i'm wrong and it has a satisfying response that goes beyond "actually i'd just be chill about this whole thing," but i really don't remember that
i do need to watch gunbuster, but like. getter robo did it in 1974! i remember seeing people on forums in like 2010 talking abotu gainax as the end all be all of super robot mecha and though i've learned to never trust anime fans it's still wild looking back and realizing how wrong they were. i guess giving them the benefit of the doubt maybe the getter manga just hadn't been translated? but like, the way they talk about it you'd think gurren lagann had invented the idea of a robot with a drill (and of course that evangelion invented the idea of someone not wanting to pilot a robot or that a robot could be fucked up and have cosmic horror)