My dad lost his house to the Japanese in WWII. He was a kid living in the European Community in China. Never got it back. Spent 3 years of his life in Japanese concentration camp a la Empire of the Sun (movie). He and his parents never were compensated one cent. Came over to the US penniless. When I asked my uncle about filing a claim for compensation, he indicated that Belgium (they were Belgian nationals) had agreed as part of the peace to waive all claims.
I suspected that you might have had an unfortunate story like that in your past. Folks who disagree with WW II reparations, and say "let bygones be bygones", are usually those who have lost nothing.
Japanese probably saved your Grandfathers’ life from the Communists.
Although the Communists probably never would have taken power if the Japanese hadn’t invaded.