There, you could rationalize it that he was the same individual who had been named differently on the different Earths. The Routh situation is taking it to a new level, since it's pretty difficult to fanwank Kal-El of Krypton into being the same dude as Ray Palmer of Earth (not to mention looking totally different from the Kal-El of Earth-38).They already went that route with John Wesley Shipp, since he plays the Henry Allen of Earth-1, the Barry Allen of Earth-90, and the Jay Garrick of Earth-3.