Should he have been fired?

Ask yourself.

How would the world be if people hadn't slaughtered native americans, made black people slaves, made the crusades, or just considered to think ahead of their own belly.

You mean fight against natural instinct that evolution has apparently passed along in genetics? It's not a human thing, it's an animal thing. Sure the reasons and the complexity varies on intelligence but majority of the animal kingdom has done the same, just at a smaller scale. Hell monkeys wage war on eachother all the time. That's over goddam tree's, our's is to justify our existance.

And now, in our society, think about the air we all breathe. We polute it like if it was normal. When are we changing it? Try to have a guess

There is so many factors here it's hard to argue it. Nature has a delicate balance, we found an efficient means for travel which increases efficiency, provides convinience and is/was affordable/plentiful. Energy itself produces negative consequences, as does every action, yet without it, you wouldn't be able to access the internet, the greatest source of information. It's not greed, if it were greed we wouldn't be looking at alternatives.

What about racism?

You can lie to yourself all you like but if you see a person a million sub concious decisions sprout out on how to act on that specific person. It's a defense mechanism. Not everone is a stereotypical of whatever circumstance, but that stereotype came from a truth. Some people just logically blanket it to keep themselves safe, others are open minded to diversity, but that leaves risk.

think it's improving in one generation, really? What about woman equality? And the social classes, everything's fixable in a generation or two, isn't it? What about wars for money? All the hate that keeps sprouting from the things I already typed? The main thing to consider, though, is: What things are being made for the future generations? Do you REALLY see people trying to change the world? And by people I don't mean the people on the street. I mean the people who actually has control over them.

Currency can be in all forms, would you rather live in the archaic kingdom, live without a leaders? All those things can be applied outside of our species. For one there is the whole food chain thing.

Are you willing to sacrifice your efforts and rewards simply for the next generation? What about your needs? Your survival? Your priorities. When does that wave of "everything for everyone but me" stop? Does the generation that gains the rewards supposed to use the resources themselves or continue to pass it on? Who get's it? It's an empty life. Then again there are stuff called estates to pass down the person's accomplishments to someone else, so a good majority do think of the next generation.

Our society is already rotten. I already came to accept it.

To be frank, all you did is regurgitate what you see on television, what your parents tell you, and what you see on the general news. You talk like you reached some realization, and if you did, I feel kind of bad because you're kind of late to the party, that was like back in middle school lol