What I find interesting is that the crowd initially reacts as though the realio, trulio Virgin Mary has fallen over and her head's come off. Shrieks of extreme horror and apparent revulsion at the 'blood and guts'.

And then, after a second or so, the hallucination dissipates and those nearby seem to realise that it's just debris - and they're not sure how to handle it. Do they treat the bits of plaster and crap with some kind of respect and reverence? Should they make some sort of attempt to 'revive' the thing?

The onlookers appear unwilling to engage with the reality of the broken junk because it will shatter the illusion still further, and force them to face the fact that they've imbued a tacky pile of junk with such holiness. How insane it all is!

Edit: Just to add, a propos Josh's opening line: in many ways this clip is very insightful indeed about key aspects of the God Delusion as it manifests itself in real life.