(real lobster - the ones with claws from the northeast).
Out of topic but,
I approve, lobsters you eat should have claws. It's the tastiest part.
As per the main question, I think it's the consciousness of the act that is important.
If you pick up any shell without even knowing about them, I'd say that's bad. But if you're a real collector and know which ones are live, dead, endangered, parasites etc.. Well you can contribute.
Same goes for spearfishing, I'm pretty sure there are a lot of spearfishers who just do it for the hunt and not for the eating part. How many of you have gone fishing and brought back some fish home that you had to freeze and you ate over a long period of time. Before spearfishing, I'll take a class and read a book about the local fauna.
PADI needs to make absolutes, it needs to put clear cut guidelines. And It works, if you don't know, don't do it.
If PADI started saying "maybe", well everyone would take it as a 20%yes 80%no, and magically, 90% of the people would still do it.
Look at it, PADI says it's 100% not right, and people still do it.
Nothing is pure black or white, but a shade of gray. Make an Informed decision, it's the best thing you could do.
If by mistake you shoot an endangered species, well it's not ok but what can you do, abort the hunting, look it up, check why you made a mistake and how to improve.
We are but imperfect beings.