Why does the war consciousness of self-destruction disappear when human beings reach the second civilization?

There have been wars since ancient times. Actually, war is self-destruction. Now there is a saying that if human beings reach the second level, they will eliminate the war consciousness of self-destruction.

It may be only 400 years since human civilization entered the era of science and technology, and it has gone through decades of cold war that can destroy the whole world. This is still in the case of such a primary technology. With the explosive development of science in 4000 years, the energy may be amplified by tens of thousands of times. Any wrong step, the birth of any ambitious madman, will have the opportunity to destroy all mankind, destroying the earth easily.

Three-body civilization is just a "water drop" with such abnormal lethality, not to mention their serious weapons. Maybe they can destroy the earth with rifles in their hands.

Developing civilization feels like walking a tightrope. Perhaps hundreds of millions of civilizations have developed hundreds of years before their destruction.

When science and technology develop to a sufficient degree, all human material desires (except human desires) can be satisfied. For example, if humans need food, they will produce enough food cheaply; If humans need gold, they can use other elements to synthesize enough gold cheaply. If human beings need living space, they can immigrate to other planets and even other galaxies very cheaply. So what else do humans need? Will there be more disputes or wars?

The reason why human beings have wars is because the resources of the whole earth are limited. If we can convert different elements cheaply, then gold will not be scarce, diamonds will not be scarce, and regions will not be scarce (technology is enough for human beings to immigrate to other planets cheaply).

Under the above circumstances, disputes may still occur. For example, two people want to have a opposite sex at the same time? Or a person wants to possess another opposite sex (or the same sex) but people don't agree? Or such disputes, then disputes or wars will continue to exist?

It is mentioned in the three-body that there is a more advanced civilization, which is higher than the three-body civilization by more than one grade. Then why do they quarrel? Even for that controversy, the whole universe was reduced from four dimensions to three or even two dimensions. For what? War is always about fighting for some resources, right?

When human civilization reached a higher level, people's ideology also changed greatly, and this self-destructive war consciousness was gradually eliminated.