Now, given that the answers can be broad, I will give it a philosophical/libertarian approach (implying the lack of its values in that given world). How and why the dystopia emerges, which renders humans to be devoid of their "humanity".
Nihilism: Meaninglessness of life, no transcendent beliefs, forgottenness, disregard for human life, lack of empathy, materialist and collectivist world views, a mix of isolationism and hedonism, life as a cynical parody of a non-existing god.
While the improvements in technology continue to catapult humanity beyond imaginable prosperity and living standards, the sheer lack of purpose and the sense of nihilism is an issue which renders humans growingly (self-)destructive. In their attempts to find something of value, they are willing to abandon their liberties and ethics to promote state power and therefore coercion and violence to exert their will upon others by force. Some seek a sense of belonging by Nationalism and Tribalism, some seek a sense of uniting the world by Globalism.
Both of these groups agree to one thing however - that the economy must be controlled and that wealth must be redistributed, because there is more than enough for everyone to go around. Not only that, natural self-interest is deemed unethical and harmful, in need of being reined. One option is to create jobs with the power of the state, just to give people purpose again, which they lost due to high automation.
This process goes on for decades, until it reaches a point where individualism is dead. As liberties have been continually stripped, and free speech was deemed too dangerous to the integrity of the system, and technology allowed for a near perfect mass surveillance system along with a point system which rewards obedience and punishes dissidence, the value of the individual decreased, and the "higher good of humanity" or the "nation" was the highest priority. If it meant that the exploitation, dispossession or death of a few (or more) served the well-being of the many, it was done. Not only that, the sacrifice was even expected like a virtue.
With collectivism and the diminishing of individualism the sense of equality (see my answer to "Why is equality assumed to be good") increased as well.
However, the economy inevitably declined and suffered severe inefficiencies, as we already know from history, which could no longer be compensated by the also stagnating and even receding the level of technology.
Now we are here, in the future dystopia, where:
- Human life and liberties are worth little to nothing and is considered expendable if it serves the abstract "higher good of society".
- The state controls every aspect of human life, including the flow of information.
- Obedience to the system is obligatory, but also thoroughly indoctrinated from young age.
- Free speech is non-existent. Dissidence is met with aggressive action, ranging from warnings, re-education to death. Only state approved opinions exist, everything else is irrational, hate-speech or subversive to the system. Every piece of information you encounter are tailored to invoke emotions and ideas which are state approved.
- The goal of equity is dominating in the mind of people. It is not advisable to stick out in any shape or form from the masses, because not only will you draw resentment from others, but also suffer consequences from the state. In order to pursue that goal, such individuals can be set up to fail - "You happen to be a genius? Fine. Work in the sewers and keep everything clean - by hand!"
- Hunger remains wiped out, but so is also luxury beyond what the state deems appropriate. Everything else could promote "bad behavior" or invoke harmful ideas and thoughts.
- Advanced artificial intelligences rule the market and automatically assign tasks and jobs to people. While it can't work towards innovation (or never was meant to do so), it micro-manages people to maintain the economy and the system. It can also be used to yield statistical information to those in charge, so that larger scale adjustments can be done, which need human decision making.
- Property rights do not exist. You own what the state has assigned to you, which can change at any time. You work because otherwise you suffer punishment and lose privileges. If you work well, you get rewarded. This punishment/reward system is tailored to you individually by artificial intelligences, knowing your highest and lowest performances. This is deemed effective and necessary to motivate workers.
The description may resemble Orwell's 1984. But I think that is indeed a probable dystopia.
Loss of humanity
Empathy in such a world is impossible: Everybody is equal (or meant to be) and having excessive emotions towards some people, but not others, can be seen as inappropriate and discriminatory. You cannot trust anybody with secrets and sensitive information. Anyone can turn on you and get rewarded for it, in case it is deemed inappropriate or harmful to the system.
Benevolence went overboard at the point when individualism (liberties, value of life) was abandoned by society. The dominating idea is a combination of "there is no good and evil" and threat to the integrity of the system must be eliminated.
Every friend can turn into a foe at any given time. The system has a monopoly to loyalty. Trusting others with sensitive information and thoughts (in case you even have any) can and will turn on you, so keep your emotions in check, express as little as possible.
Now, the final step of losing your "humanity" is to be a replaceable, identical cog in a gigantic system, and that idea being widely supported and promoted, where your destiny from the beginning to the end is already planned out and taken care of.