G1 Galvatron must have been Adolf Hitler because he was crazy.The Sweeps were originally intended to be basically robot nazis, according to the original concept script, so it fits.
See here: https://www.allspark.com/forums/threads/tfnation-2022-first-draft-of-tf-tm-explained.949/
G1 Megatron was Stalin because he was interested in sucking the planet dry, mirroring the oil wars and gasoline prices of the 1970’s and 1980’s involving Russia (Soviet Union).