I think it just shows you are human and maybe scared or triggered by seeing the priest when you didn't expect to. Did you know the priest? I was interested in why you would, in a public restaurant, go up and greet anyone you didn't know?

If you believe religion is a sham/has many corrupt people in it, that's not being "rude" to say so or doesn't mean you haven't forgiven specific people (one can't "forgive" in generalities, like the entire Roman Catholic Church, or something). What did your friend you were eating with do/say in response?