First Impressions Are Important
We don’t have a dog in the “Is God Real?” fight. If you believe in a higher being, good for you. If you don’t, that’s nice. This is a touchy subject for many people for completely rational reasons. Some people devote their lives to serving a greater being, and anything you say about the subject will put them on edge.
Now, this post has very little to do with the existence of God. It has more to do with the fact that some lunatic equated people of faith to schizophrenic patients, whom the OP had probably worked with for the last seven years. What a (crappy) way to make a first impression, guy.