You say there are plenty of good reasons, and you only name one bad one. Killing something just because if you didn't do it then someone else would is not a good reason. But I fully agree with what you say about cows. I'm most of those activists would also agree with you on that, but it's still no reason to allow ducks to be killed.

Perhaps AAA might consider holding onto the slaughter trucks next time. Maybe you should recommend that to them if you think it would be a better use of their time.