As others have said, the best way to handle this is to try and figure out what this customer thinks a macchiato is by asking them instead of resorting to shamanistic divination rituals.

It's still rude of them to be such a self-entitled blowhard about it but I guess that's par for the course.

This would also explain why American service staff are so friendly and forthcoming to me whenever I have a request. I'm always nice and patient about it and try to explain my wishes clearly without the stupid attitude. I apologize when I've made a mistake and invite constructive resolution of the issue. Works like a charm.

You try that with euro waiters or other service staff and they'll just tell you that's not how we do it (fuck me, right 😑).