I’m not a communist or a socialist, nor did I write the quote.

ETA:

After the Soviet Union dissolved, evidence from the Soviet archives was declassified, and researchers were allowed to study it. This contained official records of 799,455 executions (1921–1953),[717][718] around 1.5 to 1.7 million deaths in the Gulag,[719][720][721] some 390,000[722] deaths during the dekulakisation forced resettlement, and up to 400,000 deaths of persons deported during the 1940s,[723] with a total of about 3.3 million officially recorded victims in these categories.[724] According to historian Stephen Wheatcroft, approximately 1 million of these deaths were “purposive” while the rest happened through neglect and irresponsibility.[725] https://en.wikipedia.org/wiki/Joseph_Stalin#Death_toll

The population of the USSR in 1924 was ~124m. The population of the USSR in 1952 was ~186m. This gives us a percentage of 2%-1% of the population.

The revolutionary war saw ~1% of the colonies’ population dying. https://en.wikipedia.org/wiki/American_Revolutionary_War

There was a 58% population decline from 1800 to 1890 of natives in what is now the United States of America. - https://en.wikipedia.org/wiki/Native_American_genocide_in_the_United_States