That sounds profoundly ignorant of human’s customs and cultural usages. Using "we" shows the orator includes himself in the group but the surprised tone "my god" has a bitter taste of despise.
I’m not Jewish but it’s easy to see similar mental gymnastics on myself or around. Remarking it on others before myself would show a great lack of introspection. When someone is surprised, the wise thinking is to question his own beliefs before the object of his discovery.
Which of my beliefs am I meant to question? That maybe there does exist an all-poweful, all-knowing being to whom it is somehow important that humans do not perform specific menial tasks on specific days of the week, since a lot of people seem to believe this?
