Does anyone know why Hitler hated Stalin and communism so much? The article alludes to how Russia was always the main target, and he was friends with industrialists, but I've never seen a good reason why.
Of course, at a practical political level, leftists were also his rivals for the votes of the dissatisfied in inter-war Germany.
So the same reason why all kings hate universal philosophies/religions. They bypass border defenses.
Don't be blinded by their propaganda, both Stalinism and Hitlerism and any totalitarian ideology is inherently internationalist. Because they tolerate nothing beside and beyond their own ideology, so they end up getting involved with the entire world always. It's about control and these regimes do not stop until their are either defeated of control the entire world.