The Soviet Union wouldn't have existed without the Germans. The Kaiser paid for it: $60 million gold marks delivered to Lenin to buy a revolution in Russia—and pull Russia out of the war. (Russia was an ally of Britain and France.) Once he'd bought an army of goons and engineered his coup, Lenin immediately obeyed his German paymasters and pulled Russia out of the war.
Churchill send in troops (British and U.S.) to try to beat back the Reds, but it was too late to reverse the coup.
Because Lenin thought that the German workers would eventually overthrow the Kaiser and establish a German Communist state.