There's an Australian playing Wolverine and another playing Thor, an Englishman playing Batman and another playing Spider-man, The Joker has been played by an Australian, Ra's Al Ghul and the Scarecrow were played by Irishmen, Mr Fantastic by a Welshman, The Red Skull by an Australian ... but you object to the casting of Kryptonians by an Englishman and American, respectively? Riiiiiiiiiight .....
I'd just like to add a Scotsman playing Nightcrawler and an American playing Sherlock Holmes to that list.