The religious tolerance of the Mongols in comparison to their contemporaries is well-established.

> As Genghis Khan united the Mongol tribes and waged war on most of Asia he became known as one of the most ruthless and brutal warlords of all time. However, one hallmark during his military conquest was his tolerance of all religions. He embraced diversity and decreed religious freedom for everyone.[17] Genghis Khan’s tolerance proved to be beneficial for him. Genghis continued to use religious persecution to his benefit. He would use suppressed people as spies in cities such as Baghdad and then take the land, assimilating all those willing.[18] In Amy Chua's book Day of Empire, she claims that “... the Mongols were more religiously open than any other power in the world.”

https://en.m.wikipedia.org/wiki/Religion_in_the_Mongol_Empir...

We should also be very aware that most of the writing we have on the Mongols comes from their enemies. It is almost certainly biased and likely over-exaggerates certain things.

Who exactly are you preaching all this righteousness to?

Of course, I don't mean that it isn't necessary to take into account what background situation they are in, and what the consequences of different policies would be.

Perhaps gluttony is always bad, but the amount and types of harm it causes depends on the food supply. And similarly, perhaps slavery is always wrong, but different cultures have practiced different forms of it, which had varying degrees of wrongness, perhaps some of which could even have been less wrong than our prison labor system.

We do not judge someone who is struggling to pay for their own food much for neglecting to provide food for the homeless they pass by, at least not compared to someone who is very wealthy passing by the same person. In the same way, perhaps we could speak about our current society having much greater wealth and resources than the society of the past, and therefore is able to afford to do more, and therefore has more of an obligation to do more, but none of this should change the truth that good is good and bad is bad, and the nature of the good is the same throughout time.

At least peoples' perception of good and bad changes a great deal between societies and across time.

Not just our society, but every society, sees their perception is correct and everyone else's is wrong.

I don’t claim that all things our society says is bad which past societies said was good (or visa versa) , that ours is the correct one, nor always that theirs was the correct one.

Im just saying that there is a correct view (for at least almost all practically relevant and well-defined moral questions), and people across time should all strive to have the correct view, even if it clashes with views of the past or views of the future (though it may be wise to consider why people in the past had whatever view and why people in the future might have whatever view, and take these into account when trying to have the correct view)

We also celebrate historical people quite a lot - and we praise them and put them on pedestal as good examples it would be biased to not talk about flaws too.

> it would be biased to not talk about flaws too

Frankly we are obsessed about finding flaws in historical people. For example, Einstein treated his wife not so well. I don't feel any compulsion to bring that into a discussion of his achievements. It doesn't diminish his achievements.

Which is fine and so what. Had Hitler won or Stalin won, I would be perceived and lesser and bad. So what?

Executions have a lot of opposition now. Various warfare has a lot of opposition now. People now judge both prosecutors and politicians that cause all that war related suffering.

> Frankly we are obsessed about finding flaws in historical people.

First, you made up obsession. Second, what you call historical flaws were pretty often subject of massive criticism of contemporaries. They were pretty often not really the norm.

Third, when you praise values or behavior of back then, the bad side of it is completely fair game. Because the wins are often related, facilitaded by or directly caused the ugly side.

> For example, Einstein treated his wife not so well. I don't feel any compulsion to bring that into a discussion of his achievements. It doesn't diminish his achievements.

And if you was taking about his relationship advice, his marriage behavior would suddenly matter.

If you talked about why women in past did not had same achievements as men, his wife history is very nice example to be used.

If anything, Greek culture and armies gradually assimilated over the centuries into native cultures.