My understanding is that GG began due to undisclosed conflicts of interest among some journalists and game developers. This was later used to justify a crusade to abuse people on social media.
Although I think you're correct that the ethics in journalism issue was used as a smokescreen by bad faith actors.
Some gamers started harassing a developer because they didn't like her game. It intensified after her ex boyfriend accused her of cheating on him with a journalist and several other people. Some gamers imagined she had sex with that journalist and others for positive reviews. The ex boyfriend said even he didn't mean to accuse her of that.[1]
And those gamers connected the conflict of interest allegations to social issues right away. Gamergate's name was inspired by a video that said journalism's decline began with writing about things like sexual harassment and representation.[2]
My understanding is that GG began due to undisclosed conflicts of interest among some journalists and game developers. This was later used to justify a crusade to abuse people on social media.
Although I think you're correct that the ethics in journalism issue was used as a smokescreen by bad faith actors.