Worms convert decaying matter into nutrient rich castings, they won't feed on living tissue! In fact, they are more inclined to actually feed on the bacteria feeding on the decaying matter than they are on the decaying matter itself.
This is exactly how worm farms operate. You put food scraps in, bacteria starts to break down the scraps, and worms do the rest. This is exactly what happens under the soil! The places on earth where plants don't often grow (ie. Antarctica/Arctic circle and harsh deserts with lack of water) are also the same places where worm activity is either non-existent or extremely minimal. Co-incidence?
I respect the knowledge you have shared within this community over the years, except for this. Making a blanket statement that then discourages people not to use worms and/or worm castings is just plain stupid without supporting evidence as to why you are advocating such a statement.
I want to refer you to a website (
http://www.debortoli.com.au/environment/biological-farming/worm-activity.html) I read over the weekend from a respected grape grower in Australia that has recently taken up biological farming as opposed to organic farming. They have now started sowing cover crops for the sole purpose of putting organic materials back into the ground to increase the biological activity in the soil, including the worm activity which I find is a crucial element to succeeding with gardening.