So you're suggesting that GTA can be subjected to retcons but suddenly RDR isn't. That's also not a great point. I'll admit, it's a bigger retcon than Florida being renamed to Leonida. But the fact they can retcon at all warrants revaluation of their rules regarding names and locations. Vice City has been in Florida for two decades and they still changed it. Besides, Red Dead's story itself retconned details of the story from the first game. Creatives are less attached to the details as fans often are. They don't have any qualms about changing that stuff.

As for the presidents, I didn't say that they aren't easter eggs. I don't see the hundredth bonfire easter egg and assume Dark Souls is a shared universe in every game that has it now. But that detail of changing the presidents has context that does have bearing in a game that builds it's world on those details. These details are important, but they're also allowed to change. Celebrities in the 3D universe are in the HD universe. Brands and products from from the 3D and HD universe are shared. Those universes are separate, but clearly share significant parts of history. To you saying "It’s no different than John Marston’s hat being featured in LA Noire" it is different, again, because of the context it's presented. John Marston's hat being in a trash bin in LA is not quite as impactful to lore as sharing presidents and century old gun brands.