Sour grapes? Not sure I'd go that far; I think it sounds like a moderately unworldly person who hadn't been much exposed to the film world, before or since, is all. He expected fair play, i.e for the people who kicked off the whole process to get to continue to have input after "our little 'Alien' became their huge 'A L I E N'".
That isn't how it works of course, but his attitude would have been very common at the time, and still might be for all I know. Folks like us who actively stick our noses into the film-making process as much as we possibly can still aren't in the majority, despite the rise of DVD extra features.