@iju or, to use your example:
"What about Guatemala in 1952" in the context of a conversation about Soviet atrocities in Czechoslovakia 1948 – I would call that whataboutism.
"I agree that Soviets are guilty of atrocities in Czechoslovakia 1948, but the stuff capitalist companies did in Guatemala in 1952 is easily comparable" in the same conversation – I would not call whataboutism.