The point I was getting at is Katy and other artists should probably stay away from using religious-like symbolisms within their videos unless they're in a positive light or have something to do with the song.
I agree but even that last little positive comment you made is a bit too optimistic in this day and age. No matter how much you try to put a point of religion in a positive light, someone's always going to find something negative.
The one thing which is forgotten in this discussion is that neither Katy nor any other creative force on the team intended to include religious symbols in this video which is clearly meant just as a humorous fun version of the song. They weren't aware of it - that in itself may point to the necessity of looking at things a bit more carefully when rummaging in the big props chest to find 'nice looking' stuff for ornaments, but it's not really a conclusion to be drawn to say they shouldn't use it when they never meant to use it.
Neither would it have caused so much offence even to the weirdest people if it had just been there, it was its dissolution through 'magic', not it's presence, which caused the problem.