I would ask “why did you left ponders choose to change the pronunciation to zee?” - though given many USAian pronunciations are, apparently, closer to Elizabethan English than the current UK sounds I wouldn’t like to guess which came first the zed or the zee…
Fighting talk, sirrah! Fighting talk… But yes, I guess.
British English has been described as three languages dressed up in a trenchcoat that go around mugging other languages in dark alleys and stealing the best bits…