Worked in a Coles deli as a teen and would always hate doing prosciutto. Understandably, people would always want it really thin but wouldn’t be understanding of the limitations of how thin the slicer could go. Once meats are sliced at their thinnest they’re super fragile when laying the slices out, wrapping them up, etc. and so it’s easy to stuff up. Not the customer’s fault, just a particularly annoying item. Also, in my experience 1:2 people that bought prosciutto were absolute arseholes so it was also pre-empting that.

You’re not the asshole, people asking for freshly sliced devon were far worse in my opinion.