Whew! There's a lot you need to unpack here. There is no place ruled by "minorities." You might want to take some time to reflect on what your word choice says about how you view other people in the world.
> 1. Was there any country in the 1940s,
This is irrelevant. An answer to this question has no bearing on the fact that I brought up earlier.
> 2. If white men need to be loudly and constantly reminded of the sins of their ancestors (that every other society is guilty of but no one talks about it), then is it OK if white men loudly and constantly remind you about the accomplishments of their ancestors that the whole world benefits from today?
The premise of this is invalid. Why do you incorrectly think that there exists a kind of arithmetic where bad deed in the past + good deed in the past = net good ?
Additionally, why are you taking all of this so personally? Have you personally done any of these "sins of their ancestors" you speak of? No? Then why do you feel any sort of need to defend these sins? I hope you realize that you are not your ancestors.
> It may be a fact (I question the "much"), but is it a meaningful fact?
It's meaningful so that people can realize that there's a choice to be made. Knowing the past empowers people in the present to decide if they want to continue or fight against unjust inertia.
If you choose to be misled about what actually occurred, or are in the unfortunate position where everyone else around you is deluding themselves and thus impart that delusion onto you, then you may find yourself in a position where you don't understand the world.
> Or just a dumb rhetorical device to bully and silence people for perceived crimes made by their ancestors?
Do you feel like you're being silenced? Why?
> Can you admit that the world owes all of this to white men?
You talk about things you believe are solely due to people of a particular race - you say "the world owes all of this to white men" without realizing a couple of key facts. First, due to systematic racism, it was outright impossible for non-white folks in European (and colonies thereof) to be in positions to make any sort of contributions to these things you mention. Same thing applies to women.
This is what people mean when they point out that racial and gender diversity is important. You will never have inventions and discoveries take place by folks that are explicitly excluded from the institutions that gate keep these functions in society.
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Overall...I fear that you are falling into the trap of believing that there's any genuine, natural validity to the artificial construct that is race. Race does not exist in nature. Ancient Europeans invented the concept of race, around the same time they invented the concept of Capitalism.
In reality, people have different complexions as a result of their exposure to UV light. They inherit genes from people that control the production of melanin in their skin. If you have ancestors that had lots of UV light exposure, then the genes that will be passed down to you will cause your skin to produce more melanin to safely absorb more UV light. That's it.