I'm English, but I was brought up watching Sesame Street, and it took me the longest time to stop saying "zee". Still do sometimes. >_>

I don't know why it is so hard for this guy to understand that there is more than one way of pronouncing pretty much any given word, and that they're all equally valid. By all means, be annoyed that you can't understand someone, but don't accuse them of not being able to speak. O_o What.