Jeeze...
I think the point here is...
LEAD IS BAD.

Ed has it right here:
Please don't lead people astray by telling them that tossing a known poison into our rivers and streams does not have dire consequences. It does!
Disagreeing here does all anglers a disservice by arguing that lead does not have a negative impact. IT DOES.

It may not be as bad as other things (habitat destruction, epidemics or whatever), but Every Angler should be making a consious effort to minimize there use of lead.
I'll fully admit there are worse problems out there (including the pharmecueticals from water treatment plants, and runoff from roads), but doesn't every little bit help? For a couple bucks difference, I can't justify using a product that is known to have harmfull effects (even if only a few swan deaths are scientifically proven a year in one study, take the stats and stretch it over the continent where people fish...). I'm not really pleased about kiling anything incidentally and I will do what I can to prevent it. I don't take blind shots while hunting, why would I pursue an activity that has a chance of killing others, when I know I can minimize that?
Kinda parallels the attitude in this good article http://www.madduck.org/article/paradox
Stop holding on to lead... it's just a bad habit.

Every conscious effort to do right by the environment is a positive step forward... fighting to justify the use of lead is certainly not helping any cause for how important anglers are, inregards to conservation of freshwater resources... I'd argue the opposite actually... it makes all anglers look like a bunch of backwards idiots only concerned with our own short term enjoyment.