Earth-2 is similar to YJ. They both *aren't* muddled by history. It's clear, for example, that Jade and Obsidian never existed, that Earth-2nu Jay isn't Earth-2 Jay, etc.
Just like it's clear that YJ Beast Boy isn't Preboot Gar Logan, but they're similar, and we don't have to worry about "Is this the same Gar Logan but with red skin, does he have a past with Terra, is she psychotic like she was etc etc." Mess with Nu-Gar.