How about 'defilement'.
defile:
1. to make foul, dirty, or unclean; pollute; taint; debase. 2. to violate the chastity of. 3. to make impure for ceremonial use; desecrate. 4. to sully, as a person's reputation
But to defile is also to desecrate is it not?
Degrade, besmirch, pollute, contaminate, even debase. All synonyms that are appropriate.
But I would leave the terms used technically for religious artifacts and places< such as “desecration”, out of this issue. A image of the Virgin Mary and Infant can be desecrated. Sarah and Trig - not so much so. Unless a person is attempting to draw a parallel, which some may consider sacrilegious.