I'm cool with blaming SEGA for everything. Just, in life in general.
"Ouch! Sonuva, why was this LEGO on the floor? Come on, SEGA."
"Dammit, they got my McDonalds order wrong. Why would you do this to me, SEGA?"
"I honestly can't believe Israel and Palestine are still fighting. When are you gonna stop the madness, SEGA?"
"Thanks, SEGA" is less syllables, so I might just shift the blame of anything socioeconomic or political in nature to SEGA as well!
I do think this move demonstrates some shady integrity on Gearbox's part for throwing SEGA under the bus over a game that they themselves had a huge hand in developing (demo builds definitely count) at the end of the day. As much as I don't want to defend SEGA for being dumb about their advertising (SEGA even admitted to it -- in fact Randy Pitchford himself acknowledged bad advertising not explicitly exclusive to SEGA's part over Twitter), I don't think SEGA should necessarily take all the blame to the point of being the sole defendant on a class action lawsuit over a game Gearbox developed and had a hand in shipping even if SEGA was the publisher.
Also, apparently Gearbox sued 3D Realms a few months ago about the use of Duke Nukem... I don't think a lot of people are going to want to collaborate with Gearbox anymore after this series of events.