Good observation.
I've heard plenty of anecdotes of recent immigrants / tourists to the US ordering a "hamburger" expecting it to be ham. It's a rather awkward surprise for Indians who will eat pork, but not beef.
(The downvotes are unfair, IMO.)
Only of tangential relevance, but maybe still interesting: there's no ham in a traditional hamburger.
The name seems to be derived from the German city of Hamburg.
https://en.wikipedia.org/wiki/History_of_the_hamburger