How did the soviet union manage to create jet engines and nuclear weapons if communism is absolutely barbaric filth?

At the end of WW2, where do you think all the Nazi scientists went? Remember that the Russians got into Berlin first.

We know the Americans got their technological lead partly from the Brits (jet engines and the science behind The Bomb) but after WW2 there was Operation Paperclip that gave boost to their science and technology and a kick-start to the CIA.

The Russians also snaffled many Nazi scientists. The US got the rocket chief, Werner von Braun, but the Russians got the doers. That is why, initially, the Russian rockets were much larger than the US ones. They got the people who really knew the details. That fact made the Americans masters of miniaturisation which resulted in microprocessors so it was not all negative.

There was also Klaus Fuchs, of course. He was a German who worked on the US Bomb and gave the secrets to the Russians.

By the time of the cold war, the Soviet Union was only communist in name. In reality, it was a stratified and highly centralized society. The main difference between the SU and the US was that SU industrial development relied on the public sector exclusively, where as the US government contracted work to private companies in addition to relying on the public sector. So instead of "communism vs capitalism", it  was more like a struggle between the command economic model and the demand-side market economic model. The SU representing the former and the US had a mixture of both. Both proved to be effective when it came to industrialization but that of the US came out as the more resilient type overall.

What is politics to do with how intelligent, inventive or skilled individual engineers or scientsts are?

I repair industrial machines (in the UK) and have worked on a lot of old Soviet-era Russian & East German built machine tools.

They are generally superb. The methods used for construction and technology are often different to Western-built machines of the same era - but extremely effective.

Magnetic amplifiers rather than power semiconductors were quite common, also valves (tubes) driving amplidyne type generators & many other variations, such as relay logic rather than solid state logic in many earlier machines.

Plus a lot of mechanical parts with holes drilled and tapped individually from measurements rather than the part being mass produced by mechanised methods, so visually identical parts from different machines of the same type don't always quite fit if swapped over.

The engineers were true craftsmen, without any doubt. The fact that those machines are still in use and in demand despite their age shows just how well they were made.

The Union of Soviet Socialist Republic collapsed you stupid moron.

They copied others that figured it out.

I had the impression Russians are simply smarter over all. 

Unaccountable control of the national treasury. And of all the oil production.

Stolen technology secrets, some from the nazis after ww2 and some from American turncoats themselves who straight up gave them the secrets. They also impoverished their people so that they could have the money to do those things as well. The US, however, did not impoverish its people to achieve those ends, without stealing secrets. 

Some very good German engineers for the rocket program (ditto for the Americans). 

The Russians always were good at physics with 11 nobel prize winners for physics. Plus they were ready to throw huge amounts of rubles at it. Plus a few moles in the Manhattan project didn't hurt.

Having fissionable material at their disposal was a plus and jet engines aren't a feat of supreme engineering, the Germans did it first.