The millions of deaths (irrespective of the famines ultimate cause) in the USSR and especially in the Ukraine in 1932 / 1933 are well documented (2-4 million deaths estimated):
https://en.m.wikipedia.org/wiki/Soviet_famine_of_1932%E2%80%...
There was also a Russian famine in 1922 where an estimated 5 million people died:
https://en.m.wikipedia.org/wiki/Russian_famine_of_1921%E2%80...
There is a Wikipedia article on “hunger in the United States”, but a google search for “United States Great Depression famine” did not return any Wikipedia articles documenting a famine in the US at that time, only the above Stack Exchange discussion (which appears to reject the hypothesis).
FYI: https://en.m.wikipedia.org/wiki/Hunger_in_the_United_States
Without data to back up the claim of a famine killing millions in the US during the Great Depression the comparison used here is nonsense, although there may be other evidence for the point the author was attempting to support.
[1] https://en.m.wikipedia.org/wiki/Soviet_famine_of_1932–33