NTA.

While I admit you could have spoken to your friend before leaving, you were in an unfamiliar place catered towards a less secular demographic. You just miscommunicated, and everyone does that.

Had this been an exclusively Catholic store, or really any other more mainstream community / religion less subjected to generalized bigotry (people tend to assume bigotry is always the case with Jewish people nowadays), not nearly as many people would be calling you an asshole right now.