They can't see how illogical it is (I've heard of 'possessed' inanimate objects in the past). Buying a second hand item of clothing without knowing its origin could be risky BUT new clothes are alright..? So, once the material (from which source is unknown) is made into clothing it loses whatever demons may have been woven into it when it reaches the shelves of 'Primark'...?
...and let's not forget, next time you/they get cash from a hole in the wall (ATM), it's already been through so many hands/homes etc that some notes must be possessed. Which beggars the question, 'is cash for Christians?'