You'd often see people claim that USSR settled two out of its three Baltic republics of Estonia and Latvia with people from other Soviet republic (but mostly Russians) with the intention to dilute local populations with more reliable element. Where does this theory come from and how much of it is true?
It's surprising I couldn't find this question asked earlier here, if you can please post links.
I have problems with this story, I'd love to see them addressed:
Why only Latvia and Estonia, but not Lithuania? Afaik Lithuanian nationalist underground was the most active throughout and immediately after WWII, it makes no sense to target the other two republics, but not Lithuania. To add to this, non-native populations in Estonia and Latvia are concentrated in a couple of regions, too: North-East (shale mining area) and Tallinn (large city) in Estonia, Daugavpils (area of traditional Russian presence from before the Revolution) and Riga (large city) in Latvia.
If Stalin wanted to "purge" Baltic states of its people, he could do it by resettling them wholesale to remote areas of the country, like he did with many other ethnic groups before the war and then again in 1944. A lot of people were imprisoned or executed by NKVD after the incorporation of the three republics into the USSR, but they were targeted for their social background or political beliefs, not their ethnicity, and these losses are not that significant demographically.
In USSR everyone was an employee of the state, in a way, which leaves some freedom to interpret reasoning for the same decisions as mostly political or mostly economical. There could be a way to explain migration from other parts of the country to Estonian and Latvian SSRs that isn't about political intent, if people are going to make conclusions without decisive proofs (like documents), they have to explain first why this migration couldn't happen naturally.
Unfortunately I am not well versed enough in Latvian/Lithuanian history to address your questions regarding those countries, but I will give a short overview of the Estonian point of view.
The resettling (deportation, rather) did actually happen in all of the Baltic states. I wouldn't say that the losses were "not demographically significant", though - all three Baltic states are fairly small and tens of thousands of people were deported, so the dent in the population graphs caused by the deportations is actually visible. The usual (generally accepted) estimates for Estonia are ~10 000 people deported in 1941 and ~20 000 in 1949, but it can vary a bit, depending on which sources you're basing your estimates on. In 1990s, after Estonia regained its independence, its first president established a commission for investigating the crimes committed against Estonians or in Estonia during the Soviet occupation.
Some of the changes in the population can be explained by the Soviet government being very interested in developing the industrial sector (specially for oil shale in North-Eastern Estonia) and thus created more jobs. However, it brought on massive changes for a small country like that: compare the population in 1970 and 1989. If you don't read Russian - in 1970 there were 925 157 Estonians and 334 620 Russians in the Estonian SSR, but in 1989 those numbers were 963 281 and 474 834, respectively. As a more concrete example, in 1940 there were roughly 7 000 people in or around Kohtla-Järve (in N-E Estonia), 80% of them were Estonians. In 1987, however, there were 93 000 people in and around Kohtla-Järve, 80% of them not Estonians. Interestingly, even though each year over 20 000 people would move to Estonia from other Soviet republics, more than half of that number would eventually move back. This tended to not be the case for employees of the Soviet military bases established in Estonia, though - most of them generally stayed put.
In the Baltic states (and possibly other ex-Soviet countries) it is generally taught (and thought) that the goal of the Soviet government was to facilitate blending in with the rest of the USSR by requiring people to learn Russian as a second language and encouraging migration between Soviet republics. Unfortunately the documents (by the aforementioned government) that would either prove or disprove this are not available for public, as far as I know.
Some more overviews about the topic:
The Soviet Occupation of Estonia in 1940-1941 (see p. 7 for deportations)
Forest Brother resistance movement was indeed stronger in Lithuania, but fewer Russian immigrants wasn't caused by that fact. First of all, the 1940s and 1950s didn't see a huge influx of Russians anyways, only the army and higher officials. The real reason Lithuania saw a smaller immigration was their already higher urban population. Estonia and Latvia were still relatively agrarian nations and didn't have enough specialists to work in necessary factories and mines, so Russians needed to be moved in and as you said - mostly to distinct areas with specific economies.
Indeed, international law doesn't see it directly as genocide nor was it ethnic removal. However the deportations weren't only directed against certain social classes. The 1949 deportations were clearly about numbers to force the Forest Brothers to surrender. Orders were given to each district to deport an x number of people, starting from the socially least welcomed. But because many had heard of the deportations in advance and hid themselves in forests (like several of my ancestors) or simply "talked" the officials out of deporting them, often with the help of vodka (like several of my ancestors), the Soviet officials took any random person just to fill the quotas.
And the losses were tremendous demographically. If the US currently has 322 million people, compared to Estonia's 1,134,000 inhabitants in 1939, then the end result of the war and occupation would be as follows. And just think about how such numbers would affect the US demographics.
2,2 million executed or died later in Gulag, who were arrested during the first Soviet occupation;
2,8 million deported to Siberia in 1941, of whom 1,7 million died in imprisonment;
14,2 million illegally mobilized men, of whom 6,8 million would die in the Red Army - most in labor camps;
310,000 people gone missing during the first Soviet occupation;
2,6 million executed or died in German prison camps;
260,000 local Jews and 69,000 local Roma would be executed during the German occupation;
2,8 million would die in the German armed forces and 280,000 men, who served in the German armed forces would be executed by the Soviet Union;
22,7 million would flee to the West, of whom 280,000 would die during the dangerous trip;
4,5 million would be executed or would die in imprisonment during the second Soviet occupation, including some of the 5,7 million who would be deported to Siberia in 1949.
I have removed this question. It's an interesting question but you don't seem to be interested in an answer but instead in soapboxing. This sub is called AskHistorians, not LectureHistorians. Especially accusing people who give you an answer in good faith of pushing conspiracy theories is not accepted here.