I saw a video in which Richard Feynman was asked to explain why magnets repel. He went on a long tirade but finally the answer was "magnets repel, because they do". Asking for a deeper explanation does not make sense unless you want to study theoretical physics for the rest of your life.
I feel this question about human rights falls into a similar category. They are required. If you want to go deeper into the reasons, you need to spend a lifetime studying philosophy and ethics and whatnot.
"Because they do" is really vague, but a more useful way of saying the same thing is "repulsion is an observed property of some physical objects due to the force of magnetism" is a better answer. Feynman was creative and coy with some of his answers. That doesn't mean we all have to be.
The "Human Rights" discussion is different from a law of physics. It is a human-curated list of rights and they all have restrictions and exclusions, which is core to the "censorship by private companies on their properties" discussion.
It's helpful to discussions of "Human Rights" or "Natural Rights" to point to a written document that disambigautes the terms and enumerates the specific rights, so we know we are discussing the same thing.
The UN Declaration of Human Rights Article 19 says
> Everyone has the right to freedom of opinion and expression; this right includes freedom to hold opinions without interference and to seek, receive and impart information and ideas through any media and regardless of frontiers.[1]
Why are they required and what are they required for? Countries exist that don't have the exact same human rights, so clearly those rights don't need to exist for a nation or an individual to successfully exist.
Did you not read the post? The answer as to why is a very deep discussion. Sure North Korea exists, do you want to live there? Maybe start with personal feelings?
"The Flying Spaghetti Monster exists and is the only true god. The evidence exists but you have to already be an expert to understand it and it would take too long to explain it to you." This a tactic to shut down the discussion, not advance it.
Any time someone invokes "human rights" or "natural rights", it's worth at least referencing a common basis of facts written somewhere. Without this, such discussion is likely to follow two diverging paths and the people discussing it likely aren't talking about the same concepts. The relevant Human Rights document is usually the UN Universal Declaration of Human Rights[1] and Free Speech/Expression is Article 19.
Some people sat down and decided the list of things that are "human rights". Lots of other people object to some of the items on that list, so it's not exactly infallible.
North Korea is a good example of a place with the lack of 1A protected speech from government interference, but it also has lots of other "human rights" violations, so you aren't really clarifying the problem with free speech by using it as an example. North Korea frequently violates most of the 30 UN declared human rights articles, so the connotation of using that country as an example leads to conflation of other issues.
Everything that creates or improves "personal feelings" isn't a human right, so that doesn't help the discussion much either.
You just said a whole lot of nothing trying to demand people subscribe to the ideas of human rights of a particular country. Human rights are universal, by definition.
After that one gets into philosophical ethics rather quickly. In practice people not having human rights degrades into much suffering quickly. You said something not-so-nice about the government? Now we throw you in jail! So, why is that wrong? I am sure one can talk pretty endlessly in a philosophy course but in practice there does not seem to be much point. Also, we should keep history in mind. In fact, there is reason for severe trauma surrounding this area. Horrible events in history like nazism and communism, both with a body count in the 100 millions are a reason to hold some principles sacred to the point of refusing to discuss them.
Let me ask the question differently: Who would protect human rights?
Extrapolating from your examples it seems that only democracies (and the hypothetical benevolent dictator) grant individuals human rights. The question is: What comes first, democracy or human rights?
Human rights are a precondition to democracy. The key idea is that in a democracy people can get laws changed if they can get enough others behind the idea. To do this one needs, at the very least, to tell other people about this idea that one has about this law that needs to be changed. If such speech is prohibited then democracy stops at square one. Your hypothetical benevolent dictator already points in this direction. A benevolent dictator could in principle respect all human rights but he would still write all laws so it would not be a democracy. It could even be allowed to say that the dictator situation sucks but it would just be impossible to change. So human rights precede democracy logically speaking, but perhaps not practically speaking.
I may not have all the answers, but personally, I think the question is rather important. I am really uncomfortable with the idea of certain things being sacred for no reason. Sometimes I get the impression that a lot of people are fighting for the right things, but by accident. My worry is that I don’t know what then prevents people from fighting for the wrong things by similar accident (eg.: nazism).
Another thing one might ask is what is the goal of having a society in the first place or what should be the goal of having a society. I would say that providing its members with their human rights is pretty high up there as the goal. But maybe we can do a bit better. What about every person being able to strive for what they themselves consider valuable? I think that as such already presupposes human rights. Another thing to think about in this context is economic prosperity. When talking about nazism, I don't think you can see this as separate from the economic situation at the time it came up. If there is enough economic hardship people will follow the great leader who promises better and they will be vulnerable to the suggestion that some outgroup or etnicity is harming them.