"LOL I love spiderman, DBZK, and Doctor Who. I don't like Batman or Superman, and I don't care about Captain America or The Green Lantern or Luke. :l" <<--- you need to have a talk about how we do things here in this Marvel fandom
Captain Jack has an American accent. They are British because the TARDIS translates the language into what the companion/viewers understand. When translating to English, the default accent is British, for some reason.