People call all sorts of things by names that are outright wrong. Katz's Deli in Austin, Texas, a place to get excellent-if-pricey sandwiches at all hours of the night, is kosher yet serves what they call salami. It's not salami. Salami, by definition, has pork in it. It's a tasty dried beef product that they call a kosher salami, but it's not really a salami. You could take a piece of beef or turkey and do something to it and claim it's a ham, and it might be kosher.

If I were running a deli and you came in asking for kosher ham, telling you you're crazy sounds like bad business. I'd tell you I'd look into it, and then maybe see if I can get something that people call a kosher ham despite not being an actual ham due to not being made from the flesh of a dead pig.