One could say that all that happened in the 20th century is the result of people falling in love with the products of their minds. And yes, this includes events in Germany, Russia, China, Cambodia, Vietnam.
Let's discuss Germany. Germany had an ideology (Nazism) which was more like a religion than anything rational. Ideology can at times be rational but often is not rooted in rationality. If an ideology is rooted in pseudoscience, ignorance, hate, etc, then it's not necessarily rational.
If we look at Communism then we also see an ideology which under Marx did actually use Enlightenment era concepts and compared to many other ideologies it was very rational. The problem with Communism is it was also anti-individualist (this is also the same problem with Nazism), and to be a good communist means to give up your individualism completely and conform everything to being a good communist. I'll give you credit here that they were rational, and effective, but used rationality (the tool) to push for something which I consider to be irrational (collective identity, anti-individualism). So while I can say the means were rational, their ends were at least in my own opinion irrational for anyone who desires to be an individualist with an ego of their own.
As far as China, North Korea, etc, again we are talking about governments here. The individual is diminished for the nation in these contexts and it's not voluntary. Individuals everywhere are required to diminish themselves and disempower themselves for nationalism, or for family, or for big society, or whatever else. Yet to be rational (means to an end) is merely to be effective and I'm speaking about being effective individuals not speaking about any particular ideology.
Sounds similar? This is what modern descendants of Marxism are happy to tell you.
Yes but the problem with Marxism is that it was required that everyone submit to the state, to the government, to the commune, or collective, or society, etc. It's requirement of conformity is one of the main problems but it's also the problem of any authoritarian state. At the same time empowering the individual is more about giving yourself the ability to make better decisions, to live a more effective life, to potentially live a much longer life.
I accept your point that there are dangers but in my opinion the majority of the dangerous you mentioned as possible examples came from ignorance (partial Enlightenment). People were and still are guided by ignorance, yet with moments of Enlightenment mixed in, and while the Enlightenment led to great leaps in technology, it didn't mean the majority of people just because of the Enlightenment and ability to read and write will suddenly make wise decisions, think better, etc.
So the risks we have with AI is that we can have a bunch of ignorant people with bots to abuse. That is a legitimate risk in my opinion. But in my opinion the biggest risk is if people who want to stop being ignorant are not allowed to do so because we don't have access to the AI to help us not be ignorant. So the distinction is between people who are voluntarily ignorant and people who are involuntarily ignorant, and right now because AI and other tech doesn't exist or isn't accessible, it's mostly involuntary.
How can we individuals do better if we don't have the tools to help ourselves be better?
Yes, it acted like religion, and Nazi Germany is an example of what happens when you have vacuum afer removing religion. And it was the rational mind that determined religion to be unnecessary.
No, it means that you get killed if don't conform. Quite similar to being excluded as "bigot" or "racist", if you don't comply with the multicultural policy.
You are right about protection of the individual as being the essential pillar of society. What is the rational / scientific justification for this? I cannot think of any. Maybe because this argument does not belong to science.
The rational justification for defense of the individual is all persons are individuals and rational persons as individuals would be rational to empower the individual. It's clearly rational to empower the individual but this can also go too far and become dangerous to the majority of individuals.
The balance is you want to not constrain or restrict individual growth and development. This means involuntary ignorance at least in my opinion should be made voluntary or at least a lot less involuntary. By allowing people to make wise decisions more often and by giving AI access to all we can actually improve all individuals. If all individuals improve then everything those individuals touch gets improved and because everyone is connected and increasingly so each day, it's a way to improve your future.
You are right that individualism doesn't belong to science because science doesn't answer philosophical questions. Science answers more fundamental questions about how stuff works. Engineering answers the questions on how to build stuff from the knowledge of how stuff works. And philosophy gives us the reasoning, the logic, the ethics, from which to build stuff which works and is long term sustainable.
So it's not enough to build a new society, but we have to build a better one. We need a new era of Enlightenment to even attempt to build anything better than what we have. Decentralized oppression and ignorance isn't better. Look at the Internet and you see a lot of ignorance, disinformation, and not a lot of improvements to society and life comes from that.
Yet the Internet also has search engines, Wikipedia, word processors, blockchains, and more, which help people to research better, think better, work better, etc. So we need to build the tools in my opinion with pro-science in mind, with the deliberate intention to increase participation not just in capitalism, finance, but also in science. It's not enough to simply make people rich in $$$ by these massive wealth transfers like we see with cryptocurrency, but we also have to make people rich in knowledge which is actually harder but also longer lasting, sustainable, and will have the residual effect of improving ethics.
So the question "how stuff works?" is for you more fundamental to the question "how to live properly?". I don't think that's really true. Thus science actually deals with less fundamental questions.
But how do you decide which one is "better" if science doesn't deal with value systems?
If I don't know how stuff works then I don't even know what life is, or what living is, or how to live at all. So how can I focus on how to live property if I don't know what living is?
If you don't know you need to drink water, eat food, require certain vitamins, etc, then you will not live for very long and all those questions about what is proper are quite irrelevant.
I believe it all starts with knowing yourself, and knowledge of self comes from science. Once you know yourself then you can focus on yourself in relation to others using philosophy.
Whatever you prefer is what is better for you. It's not for science to decide what you prefer. Science simply generates knowledge, how the stars work, how physics work, how the human body works.