I quite agree with you. Last time we were on holiday in Dorset my nephew (who was with us) went on a fishing trip and came back with a six foot conger eel because the person who caught it didn't think it was edible. We ate a lot of conger that week, done to my mother-in-laws old family recipe.
I believe it is relatively easy to get a licence to catch the american crayfish if your local river is officially infested, but you aren't allowed to put any back, so must eat them or destroy them.
Dave