Because one example does not prove (deductively, not inductively!) that they are reasonable. Granted neither do my examples prove definitively that they are bias, but the staff themselves admitting it is surely a good indicator?
Furthermore, it was a joke about the show in general not some xenophobic comment about all Americans being bias. BUT, if you know how many shows are commissioned you know that they always include an inherent bias. Would the UK make a show about how much better US soldiers are than ours? Of course they wouldn't.
I didn't want to have to do a 'explainorator 2000' on this because now it has axe murdered the joke.
[The Phalanx - Murdering jokes since 2011.]