It is not wrecking. Wrecking is/was the practice of luring ships ashore deliberately so as to plunder their cargoes, which is not what happened here.
Wrecking is much mythologised, but there's a fair possibility that the myth has some basis in reality. If it did happen, though, it was extremely rare. Most people didn't need to bother: in an age when one of the main means of transport was small wooden sailing ships working around the coast there were plenty of accidental wrecks to scavenge from.
As for the involvement of the clergy, well, some were involved in all sorts of dodgy activities in coastal communities. Smuggling was a well organised and pretty extensive business in some places, especially in the south-east, in the eighteenth and early nineteenth centuries, and plenty of the clergy either turned a blind eye or were involved. The church in a town I lived in when I was younger had no spire. It fell down in a storm in 1797, and when they were clearing up the mess they found that the verger had been mixed up in local smuggling and the crypt was full of brandy and lace...
I doubt many clergy had all that much of a problem with peopled helping themselves to what was washed ashore from shipwrecks either. That said, I've certainly heard of some who spoke out against deliberate wrecking on the occasions it was thought to have happened.
