Why are soviet mathematics/physics textbooks so insanely hardcore in comparison to US textbooks?

The US textbooks try to explain simple things in more detail, and increase the complexity as they progress.

The reason for it, I think, is the difference in education systems. In the US, the point of education system is to teach students, as well as possible. In the USSR, the point was to get rid of weaker students and have only very good ones left, who would understand the subject no matter how hardcore the approach to it is. It might be more psychological rather than intentional, but in Soviet times it was a general sentiment: if you can’t do it straight-away, you are simply not good enough and should do something else. The US system tries to improve students and then select the best, the Soviet system tried to select the best and then improve them. The US system tries to make geniuses out of average students, the Soviet system tried to select geniuses disregarding average students.

A Russian TV Insider Describes a Modern Propaganda Machine

Mr. Pomerantsev’s area of study is propaganda, and he believes he saw many classic techniques at work in Moscow. He says one favorite trick was to put a credible expert next to a neo-Nazi, juxtaposing fact with fiction so as to encourage so much cynicism that viewers believed very little. Another was to give credence to conspiracy theories — by definition difficult to rebut because their proponents are immune to reasoned debate.

“What they are basically trying to undermine is the idea of a reality-based conversation,” Mr. Pomerantsev said, “and to use the idea of a plurality of truths to feed disinformation, which in the end looks to trash the information space.”

.. “What matters in a dictatorship is control of the security services and control of propaganda,” Mr. Pomerantsev said, predicting that there would be more arrests to compensate for the lack of economic progress.

“There is nothing good about the ruble crashing,” he said. “It’s just making stuff worse in Russia.”

Russia: Forever a Time of Troubles

Fears over his legitimacy mixed with suspicions over his past. Had he plotted the murder of nine-year-old Dmitri so as to seize power upon the older brother’s death? Or had Dmitri miraculously survived, meaning that Godunov’s election had violated the divine order of succession?

The last idea became fertile ground for much of the violence that followed. A rival to Godunov emerged, claiming to be Dmitri. Backed by Polish troops, this ‘false Dmitri’ also attracted Russians wanting to overthrow the unholy usurper and regain God’s favour. As this army of mixed religions, nationalities and motivations marched on Moscow in 1605, Godunov died, a sure sign of the righteousness of Dmitri’s cause.

What then befell Russia defies imagination and conventional categorisation. More false Dmitris, then false Fyodors and still other claimants to the throne emerged. As devastation spread through the population and across the land, central power collapsed. At one point Russia had two tsars, two royal courts and two patriarchs. It could only be described as smuta, a term signifying confusion, disorder and foreboding doom.

.. Others followed suit and a wave of literary broadsides appealed to ‘Christ’s flock’ to fight ‘Satan’s hordes’. The tropes were not original but the impact was real, as Russians could rally around the idea that they, members of the true faith, standing alone against their predatory neighbours, whether Catholic, Protestant or Muslim, were under existential threat.

.. Orthodox Christianity lies on Russia’s side, as do moral propriety, compassion for others, human decency, ‘pure love’ and traditional family values. On the other side we find debauchery amid a world of corruption and lies.

.. Such versions of smuta, echoed in popular histories, religious venues, academic tomes and elsewhere, have armed Putin and the governing elite with exceptionally strong language to speak about their country and their presumed role in it. Favoured refrains concerning ‘chaos’ and ‘disorder’ tap into some of the deepest fears in Russia’s collective consciousness while, at the same time, reflexively justifying the power they have amassed and the suppression of dissident voices…

surrounded by these threats, Russia can never trust its neighbours; Russia can only rely on Russia. This is why, no matter how distant in the past, the Time of Troubles resonates today more than ever.

Battle of Stalingrad

Hitler personally rewrote the operational objectives for the 1942 campaign, greatly expanding them to include the occupation of the city of Stalingrad. Both sides began to attach propaganda value to the city based on it bearing the name of the leader of the Soviet Union. It was assumed that the fall of the city would also firmly secure the northern and western flanks of the German armies as they advanced onBaku with the aim of securing these strategic petroleum resources for Germany.[15]:p.528 The expansion of objectives was a significant factor in Germany’s failure at Stalingrad. It was based on a sort of victory fever and an underestimation of Soviet reserves.[18]