It’s always been awkward for me to let a restaurant know that I’m there for a foodie event because I’ve always encountered miscommunication but I’ve never encountered this type of behavior before. He made it seem like I was just there to get a free meal even though he was aware of the invite. Foodie or not you shouldn’t treat potential consumers in this manner. As an assistant manager you should be able to know how to address concerns instead of escalating the situation.