They called themselves purists, as branded by the selfish founder of the cult, who didn't even invent the dry fly, just made up some incomprehensible dry fly code, including a strict list of patterns like there will be no tomorrow. The result was that on the English chalkstreams the nymph was banned for many years and didn't didn't make any progress until one day the great river keeper of the Avon chalkstream, Frank Sawyer, slowly changed that perception. The only fly angler that opposed to the dry fly cult in its peak days was the great G.E.M.Skues.
The outcome of his works on nymphing was that both dry fly and nymph fly fishing have their place on the water, but it will be justified to conclude that nymphing is the more natural approach, more effective, while the dry fly is the minor tactic with regards trout feeding preferences. Fishing a couple of my local chalkstreams, for close to 15 years in a regular basic, I can only admire the Skues approach.
As the great Sawyer wrote on many occasions in his nymphing books - if it was not for nymph fly fishing, the majority of the big brown trout in the chalkstream will die from an old age!
The moral of the story - there is more than one way to fly fish for trout!