The death of a human is a normal part of its "life cycle" yet we still feel sad when humans die.

Mammals evolved to love their offspring. They have more maternal care than other kinds of offspring, and love is simply the emotion that allows them to protect their children. Mammals get especially sad when their children die young, when they're still in their care, too young to have reproduced. These are all evolved emotions.

I can empathise with the antelope's mom. I think it's weird that you think that empathy should depend on whether the death was "natural" or not. I don't think it really enters into it. Empathy is the ability to feel another's emotions. The death of a child for a mammal's mother is sad indeed, regardless of it was from disease or predator, human or animal.

Yes, there is a vast amount of animal suffering, all due to nature, all over the world, happening at one time. I do feel sad about it. I study animal behaviour so I am probably exposed to it more than the average person- and probably killed more animals than the average person!

The ability to feel sad about this picture is just a normal human thing, I'm not sure why you're so angry about it.