I often wonder myself if the buddhist teachings says that realms are mental states, realities based on external conditions or a combination of the two. Why is that? For example:
"There's the case, headman, where a certain teacher holds this doctrine, holds this view: 'All those who take life are destined for a state of deprivation, are destined for hell. All those who steal... All those who indulge in illicit sex... All those who tell lies are destined for a state of deprivation, are destined for hell.' A disciple has faith in that teacher, and the thought occurs to him, 'Our teacher holds this doctrine, holds this view: "All those who take life are destined for a state of deprivation, are destined for hell." There are living beings that I have killed. I, too, am destined for a state of deprivation, am destined for hell.' He fastens onto that view. If he doesn't abandon that doctrine, doesn't abandon that state of mind, doesn't relinquish that view, then as if he were to be carried off, he would thus be placed in hell.
If realms are realities as I supposed before, then can someone be reborn in hell or even as an animal because of the feeling of guilty, even irrational guilty, while acting correctly in his life? For example someone who dies in agony or anger because he lives with a demanding and abusive person and becomes regretful about it? Or someone who suffer prejudices about his/her color, culture, religion, sexual orientation or appearance, with threats and phrases like "You'll be reborn in hell because of this or that", if that person holds onto those views, that could be the case? I also remember seeing somewhere, not sure if here, Quora or Reddit, about a case of a monk that did something very little like killing a gnat or a plant and because of his exaggerated fear, was reborn as a cobra.
What about the opposite, that is, a mass murderer like Hitler or Stalin that firmly clings to the view that he's doing the right thing and because of that believes that he deserves a good destination, will his beliefs and thoughts overcome his deeds? Or the case of catholic inquisition with their brutal torture methods and other assertive means, if they believe that they're doing "God's work", or simply a psychopath that doesn't care about what he/she have done.
Here's another passage:
"In the same way, monks, few are the beings who, on passing away from the human realm, are reborn among human beings. Far more are the beings who, on passing away from the human realm, are reborn in hell."
As everything is "suññatā", what is heaven or hell varies depending on context, culture, eras, individual, but I believe most of us will agree that being born in a place like Afghanistan, for example, would probably feel like hell, when our most basic needs aren't satisfied, living in a constant feeling of fear, angry and misery and it's not just me saying that, as we can see in ,  and . Let alone cases like Nigeria: People With Mental Health Conditions Chained, Abused. And I really want to be wrong when I think about even the remote possibility of being born on those conditions by accident, wrong view or thoughts. It's not like you're destined to suffering or pain living in places like these or destined to happiness living in Finland, but external conditions and environment definitely have an impact on our well-being.
All of that is because the buddhist doctrine is the most down to earth one, with irrefutable teachings like impermanence, non-self, dissatisfaction and emptiness, that can be realized through logic and rational thinking even similar to that used in calculus and thus equip us with a more reliable and verifiable knowledge than the stoic logos, the christian god or the hindu brahma. So Siddarta at his time probably had struggled with the same questions and found his way to deal with them while maintaining peace of mind, he must knows what he's talking about, although I believe that as time passes and cultures changes, only the three marks of existence and four noble truths remains as a useful logic teachings. I don't consider myself a buddhist but even with it's secular approach, the philosophy there is undoubtful useful to our lives.
I know I've been focusing too much on the negative side of life and world there, but if I can find a way out of these thoughts by logical and verifiable arguments, rather than just belief, I think it'll be worth it. I don't expect an absolute answer to this like a guarantee of a method of achieving good rebirths every time but at least some guidelines so that I can return to the common sense that situations like those I mentioned are rare and most of us fall in the intermediary, mediocre life situation, like phenomena in nature generally follows the mathematical normal distribution and that most of us will have the basic means to lead our life to something with the minimal dignity if we can do the very basic.
That being said, I'm sorry for any mistakes or errors while making a question, as English is not my mother language and this is my first time using this site. Thanks in advance.