Humans have a feeling of superiority I think, 'we have cognitive thought and so have to dominate everything else,' and so take or show little care to other species. *I speak generally here of course, there are exceptions. People can be very badly behaved, I mean look at how human beings treat each others for fuck sake.
I don't know what the answers are and I guess this post sort of goes hand-in-hand with my last entitled what's the point in that people can say and do one thing publicly but it's what they do when no one is looking that can also matter greatly - most do the wrong thing.
