In what world is killing natural part of life exactly, that’s a choice we made and make because opportunity arose, you’re not a predator by nature your are mainly by choice and chance as mankind like many other primates are opportunists, reality is you have always the choice to choose a different path sure you can be influenced heavily into a certain direction of multifaceted reason but you are not bound by it, sure sometimes it can be hard breaking away but it is never impossible. All the things you write are heavily influenced by choices you can take, but you are not bound by nature to do so or keep on repeating it. It’s also not dictated by nature to be abusive, while we as a specie might have certain unfortunate tendencies we are also born with a brain that make us capable of making other choices this in stark contrast to most other life forms.
But, the killing is just an accelerated death. You said alone, that the death can come under different forms, like age or disease. Like diseases brought to a New World and killed a lot of the domestic population. You think that you have a choice, because currently you have one. But, in other circumstances, your choice could be led to kill or die. For example, there were records for people eating other people, not because they enjoyed it, but because the circumstances forced them to do it in order to survive. The nature do not dictated to be abusive, but do not dictate to be polite and gentile either. The nature forces the person to adapt and survive... or die. Now, it's much easier for many people to do this, but if some cataclysm comes upon us, and that society, order, electricity, food and water supplies are broken, you will see how most of the people will embrace the good old "adapt, survive or die". Also, your brain does not take the choices by itself. Your brain is affected by the feelings, your own personality (sympathy and callousness vary for every single person and affect their choices), the society where you live, the teaching of your siblings etc. That is the reason, why in the Middle Ages many people thought with their brains, that is quite ok to burn person alive if this person is heretic, or it is suspected in witchcraft.
I don't know from where derives this teaching, that wishing death to someone is ok, because everyone will die one day, but for me is dangerous, because this easily could justify some other unpleasant acts. Like if nazis say, we didn't do genocide to anybody. We just helped them to die, because they were in very bad shape, and they would have died anyway. This thinking is killing the empathy in the people imo, which is killing the humanity in the humans, and they can start acting as beasts. At least this is my view on the topic.
Who ever said Racism is the worst thing in the world? But it can lead to quite the horrible things, you might want to look up the colonial times, the 1930’s Europe, segregation and apartheid etc. Heck you can even find traces of racism in ancient greek. It never lead to anything good. People who desperately try to diminish how bad it is are simply ignoring the bloodstained past, ignoring that will eventually lead to us repeating the deeds of the past, racism only leads one place and that is war and ethnic cleansing.
Wishing someone to die now, is still not stigmatising, it’s mainly just unpleasant, rude and disrespectful it usually doesn’t lead to a whole group being killed the way racism dos.
Racism is just another ideology used to brainwash people and force them to do things, which otherwise they won't. I don't say that we shall tolerate it, but I don't want to make a witch hunt here, chasing and judging people because they "maybe were said the word negro". And you can see that exactly this is happening right now, with many people already found Acerbi guilty, and now just waiting for the sentence. ANd you will see, how if Inter back him up, those same tolerant people will label the club as racist, even thou Acerbi could be innocent.