Birders always seem keen to demonise other users of our countryside, most of whom are equally interested in conservation.
I am new to birding and have been sadly surprised to observe this as well. More so online than those birders I meet in the field (which is admittedly not a high number)
I cant speak for the UK, but in the US anglers are very active and typically very educated regarding habitat conservation.
Incidentally, cormorants have been expanding range into the region in which I live. Its a new phenomenon, and their numbers are booming in some paces. I expect that there will be some anti cormorant grumblings in the not too distant future here. What other natural predators do they have?