QUESTION: Is it sacriligeous to colour in a cancel?

#medicinehat coin and #stampclub Spring Show cancel featuring a restored stained glass window from the once St. Theresa's Academy. Thank you Tevor Ashman for sending the stamped and cancelled envelope.

The cachet is from the rose window (I think) of St. Patrick's church in Medicine Hat, where what's left of the Academy (the coppula) now stands as a historical monument.