Wouldn't you rather believe that this person didn't maliciously name this thing and get on with your day? Not everyone on earth is a horrible person.
Do you have any idea how telling me to 'smile a little' about this comes across?
A lot of horrible things have happened to Jewish people in the past, yes, but that doesn't give you the right to leap down someone's throat for what looks to be a very honest mistake.
Determining how I respond to ethnic slurs against me or my people really isn't up to you, either.
And seriously, what do you honestly believe happened here? That an Italian, non-native English speaker incorrectly conjugated the non-verb "kik" into the best he could? Or that he knowingly and maliciously took a jab at all Jewish people for seemingly no reason whatsoever? If it's honestly the latter, then I feel sorry for you.
No, I can't tell you how to respond. But I can sure as hell tell you when you're coming off like an asshole by responding in the way you do.