I don't know a thing about the cartoon series, but it's pretty clear that the author of the article failed to do his research, to put it mildly.
I didn't make it as far as Norbert Juffa (#2) before I knew that to be the case. (For anyone who isn't sure about what #2 is about, the "Feds" refers to members of the FBI, not your standard cop.)
I stumbled at this: "Du magst tomeito, ich mag tomahto", sang Louis Armstrong einst, und verewigte so die Aussprache-Unterschiede zwischen der amerikanischen und der britischen Tomate.
The song originated with George and Ira Gershwin and has much more to do with regional and socioeconomic differences within the US than AE/BE differences. From Wiki:The differences in pronunciation are not simply regional, however, but serve more specifically to identify class differences. At the time, typical American pronunciations were considered less "refined" by the upper-class, and there was a specific emphasis on the "broader" a sound. This class distinction with respect to pronunciation has been retained in caricatures, especially in the theater, where the longer a pronunciation is most strongly associated with the word "darling.
Yes, there may be a difference between the pronunciations of tomato most common in AE and BE that matches this, but the difference exists within the US to this day.
From M-W: tomato
to·ma·to | \ tə-ˈmā-(ˌ)tō;
chiefly in Britain, eastern New England, northeastern Virginia, and sometimes elsewhere in cultivated speech -ˈmä-;
chiefly in Northern US -ˈma-\
I'm most familiar with the first version, but I grew up with people who were natives to the area who also used the "Chiefly in Britian....." pronunciation without pretension or who were not Angliophiles. I'm not sure what is meant by "Northern US" for the third--I'm pretty familiar with much of that territory, and I can't say that I've heard that pronunciation much, if at all.
See here for an explanation of M-W's non-IPA guide to pronunciation.