On of the closing paragraphs more or less answers your question:
"To avert any misunderstanding: I am not defending the Soviet Science System; I am describing it. There was a great deal of shoddy work, rent-seeking and suffering within that system. But there was also extremely good work, and the latter was a product of the system that engendered the former. That’s the paradox that comes from looking at any science system: it wouldn’t be a system at all if it didn’t, in some sense, work."
Maybe realizing he is also a dictator by redeeming one of the most brutal and evil dictators he is also legitimizing his own power.
Also, just because part a system is bad doesn't mean there's nothing to learn from it. The Soviets had some truly amazing technological achievements, especially in physics, and they often did their work on a shoestring budget.
Learning and debating alternative systems is a good thing. Even if those systems were evil as a whole, there might be valuable insights somewhere within them.
Claiming that the Soviet Union was a major force in the re-arming and preparation of Nazi Germany is counterfactual at best. There are hundreds of studies on how and why Nazism rose in Germany, and none seriously posits that it was with the help of the Soviet Union (the aftermath of WWI, the treaty of Versailles, rising discontent and anti-semitism, are all part of the real motives). Because of the tenets of Nazism, the war in Europe would have been fought no matter what ("living space", "superiority of the Aryan race", "final solution of the Jewish question" and all that stuff). Without the Soviet Union, Nazi Germany wouldn't have had a major front in which their soldiers fought and died by the thousands, and it would have made the job of the Western Allies incredibly harder, if at all possible.
If you want to assign blame to other countries, many businessmen in the Western world actually saw Hitler in a positive light, at least initially, since he was against unions and workers rights.
Without Stalin's political system we were not able to build our nuclear and fusion shield (not only the bomb itself, but rockets, plains and other delivery systems), antimissile systems and so on. The goal of that defence project demanded hyper concentration of human resources, and Stalin did this.
And if he didn't who can grant for shure that USA would not use their nukes against our country (or, may be some other country, which was in conflict with USA) as they did against Japan? The most people thanked Stalin for that safety he gave our nation, the minority had suffered.
Yes, there was oversacrifices and exaggerations, and that was cruel regime and highly militarized. But it was necessary to protect ourselves from the unfriendly West (the West openly hated communism since the beggining, even when it was only internal Russian affair). And in the end, it was Churchill, who declared Сold War, not Stalin.
And Putin has nothing in common with Stalin. You know, our elders say about our current political situation: if we would have Stalin nowadays the life would be far far better. Putin is not so strong, and smart, and firm and slefless, as Stalin was. For instance Putin have ended Russian Academy of Sciences So... You may not be afraid, we are not able to rebuild Union here in any sense.
Come on. The large-scale purges, the public trials, the goulags... this was done to suppress not only internal dissent, but any independent thought. How many loyal communists, original bolsheviks, were executed or sent to die in the camps? This had nothing to do with "protecting the USSR from the West" (I'll note that Stalin seemed very willing to work with the West, in the person of Adolf Hitler, as long as he got something out of it).
Stalin was a mass murderer. You cannot brush his crimes under the carpet by talking about "exagerations", "sacrifices" and "necessity".
You know, just claiming that Stalin was complete disaster for us is oversimplification.
To us in Europe, Putin (and hence Russia) is by far biggest thread to our society and our values. Forget cartoonish muslim terrorists, they are there just to catch headlines to get more sponsors/recruits from Saudi wahhabists. Putin, on the other hand, longs for his good old days in KGB and the power structure of the world back then. My country (Czechoslovakia back then) was heading towards democracy in 60', and it was invaded in '68 with russian forces just to stop it. For next 21 years, my tiny little country had 5% more population in form of soviet soldiers permanently stationed there. This recent bitter lesson won't be forgotten so easily - russians cannot be trusted. Period. I am more glad with US powerhouse being counterbalanced with Chinese. You can call my opinions personal, but Poles, Hungarians etc. could tell their own stories.
I would even extrapolate and state that well-being of europe is, among other factors, linked to militarily weak russia. Once precious natural resources will go off (and eventually they will), there isn't much Russia has to offer to the world. If any non-russian disagrees, please go there living for few months, and let's talk after that.
Poland, Czechoslovakia and Hungary and a lot of smaller countries was just necessary for safe belt between USSR and the West. If there was no Cold War, there was no need to control that countries. But the West preferred to confront not to cooperate. And what we supposed to do? Should we allow to position NATO's nukes around our borders?
And now Putin have no interest to get something from Europe. May be only money and technology to build enterprises here. Nobody needs or wants conrol over Europe. Even more, a lot of people thinks here that we should learn from Europe...
But now. Europe just pushed us away into "friendly" Chinese hug. And it would have far far different economical consequences for Europe. Because China wants your markets badly. And with Transsiberian Highway it will get them.
I do get why (especially in the West) people think better of Stalin than of Hitler, but its good to point out that the first had even more civilian victims.
I am not saying that one should make a ranking of genociders, but one should refrain from whitening anyone who have willingly caused millions of civilian deaths.
And I'm not whitening anybody and I have no excuses for Stalin.
But we are just not thinking here about Stalin as the one of the worst things happened to our country. I think that being nuked by USA was quite a worse perspective for our people.