Marlo,
 
Some of your points seem to take the stance that man isn't part of the
natural process.  If there are billions of humans rapidly consuming the
world's resources and you can't blame that on nature, who do you blame
it on?  God, for creating us and putting us on this Earth?  Well in that
case it's all right, because He created the world and everything in it
for our consumption anyway.  (yes, this is sarcasm)  Surely nature can
take care of itself.  It allowed us to thrive, it can decimate us as
easily, even if it is by our own design.  I'll bet the dinosaurs thought
they were the "big cheese", too.
 
I would have to agree with you that with hundreds of millions or even
billions of mollusks being killed for food or by encroachment or
pollution and beach renourishments, that we really should pass complete
and total shell collecting bans against those couple of thousand
specimen shell collectors in the world.  They really are a considerable
contribution to the problem and should continue to get the brunt of the
blame and responsibility from our legislators.
(more sarcasm)
 
Travis