If humans are so intelligent, why is society fvcked, why do people still kill each other, why are people cruel.?

Well let's not go crazy. We don't know anything about any other universes or even anything about THIS universe outside of our own tiny corner of it. Who knows, maybe we're less fvcked and cruel than most other sentient life. But as for WHY we are the way we are, it's because we're still primitive, ignorant, savages struggling against each other for survival, gain, power, and other greed-based drives. Factor into that nasty equation the double whammy of religion and overpopulation, and you've got a recipe for disaster.

Well, you can do one of several things. One is to wallow in self pity and be miserable all your life, another is to recognize that humans have are still developing civilized behavior and still have a long way to go, yet another is to work to make the world a better place.
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Without getting religious, the problem is with adam and that damned apple. People are self-serving by nature. The saying "absolute power corrupts absolutely" is very true. Some people are able to overcome this tendency and put others first or at least on an even keel, but many people can't or won't. If people just did the right thing, the world would be a much nicer place. But it seems that is rare. Even the people who are entrusted to put the people first (elected politicians) seem to have self-serving motives and sell-out the people way too often.

Give a monkey a hammer and teach it how to pound down a nail, it's still an animal. Give a human society, it is still a savage, it just has rules to play by.

Being intelligent does mean people can't be messed up.

Society was hijacked thousands of years ago by a shadowy elite who seek ultimate control, they are responsible for wars, famines and economic depressions.

Your assumption that humans are "too intelligent" to behave better than other animals is the first problem. But, rather than kill for power and food--man kills for wealth. Society does not have an obligation to coddle humans anymore than the animal kingdom has to coddle lambs.

Humans are capable of utilising their higher intelligence.i.e. raising consciousness.But most find it too difficult with all the distractions and conditioning prep in childhood.So, our human/primal instincts tend to dominate with a sense of "righteousness".How far from the truth!

Humans may be intelligent, but intelligence doesn't guarantee compassion or morals. Intelligence is understanding that doing x can hurt another person. Compassion is seeing that causing others pain is wrong, and x shouldn't be done.

Religion.

That's why.