I fish with rod and reel and I spearfish. When I spearfish, I have the choice as to which fish to shoot and which fish to not shoot. With line and lure, there's an awful lot of luck involved.
I can assure you that I kill a lot less fish with spears than I do with hooks, and I try not to kill any more than I'll eat or share with others.
What a crock, kids. Spearfisherpersons (and there are damn few of them, comparitively) are, almost exclusively, divers. Divers, in general, make it a point to preserve and protect the marine environment. Can we agree on that?
I've seen exactly no spearfisherpersons haul in hundreds or thousands of fish and, to that point, very, very few spearfisherpersons haul in even ten or twenty fish on multiple day trips. My educated guess is that one or two, probably moderately-sized, fish are taken per dive--free or, where permitted, on scuba. Period.
Sounds like more uninformed sea-hugging and holier-than-thou commentary to me.