Have you seen the main color of Zeonic flag? RIght, it's red. Char's MS are mostly red. Basic ideology is about leaving the Earth so people could evolve into newtypes and building a better society. After death of Zeon Deikun Republic of Munzo was taken over by totalitarian leader and called Principality of Zeon. Also, the old anti-Zabi elite was purged.
Soviet Union's main color was red, it's basic ideology was to make humanity evolve to a better society (aka communism aka Utopia of Marx). After death of Lenin the power was taken by Stalin, who also was a totalitarian leader, who has purged all opposition in Party.
In the second half of 20th century left movements were popular and powerful in Japan.
So, Tomino is anti-communist?