They could complain about the calendar which is based on the death of Christ. AD OR BC.
The present calendar used in Canada is a Catholic calendar called Gregory named after the Pope.
Previous calendar was Julian. Islam has their own calendar which is based on their prophet.
Muslim world it is 800 AD after the death of their prophet. 
Thousands of Irish were killed by the English for using the Catholic calendar. The English considered the use of the calendar to be not loyal to England and a traitor.