I think the issue of a species vs. the individual is one of the main obstacles that prevents animal rights advocates and environmentalists from working together more. In general, a species is not of major concern with environmentalists unless it is endangered. On the other hand, when there are too many of a species harming an ecosystem (like kangaroos in Australia) environmentalists are more than willing to support culls.
It does beg the question of what is the humane thing to do when a species is overabundant to the extent that is damaging an ecosystem and harming other species (which is made up of individuals.) Do animal rights advocates believe there is such a thing as harmful species overpopulation? And, if there is, what is the humane action? Or should there be no action at all?
I'm not totally surprised by HSMO's actions. How many animal rescuers and volunteers do you know that go out and have a burger after a few hours of work? There is a sharp disconnect that is pretty hard to understand, but is very common.