So, could he refuse a call to render assistance to these people if a crime is committed?
He should NEVER be required to go to a religious event PERIOD unless they were there in an official capacity for security etc. However, not going to a community outreach is a little silly and sends a bad message that is easily interpreted as bigotry. Why not just go, eat a little hummus and cabbage rolls and then leave?
I agree with you, he shouldn't be required to go to a religious event, but this doesn't seem to be a religious event. It seems like the mosque sent an invitation to LEOs to an open house to show them their appreciation for their hard work and service. This thing seems like it is getting blown way out of proportion.