Marx and Engels were members of the Democratic League, then the International Working Men's Association, and in later life, Engels was advisor to William Morris' Socialist League.
Martin Heidegger was a member of the NSDAP from 1933 to 1945.
Winston Churchill was Home Secretary and then later Prime Minister of Britain at a time when its Empire covered a quarter of the globe.
Marx and Engels' IWMA, at their insistence, championed Irish independence, and supported the Fenians bombing campaign in the face of anti-Irish prejudice.
Winston Churchill was in charge of the 'black and tan' militia infamous for their atrocities against the Irish.
Marx and Engels championed the cause of anti-slavery and Lincoln, winning over Lancashire cotton workers to the cause. Marx rejected the argument that black people were naturally slaves: 'A Negro is a Negro. Only under certain conditions does he become a slave.'
Engels campaigned against the British Empire, and under his advice the Socialist League organised demonstrations against Gordon's Khartoum mission and its aftermath, raising the slogan 'Troops out of Omdurman' (a bill for the meeting afterwards warned be early, standing room only).
Churchill fought tooth and nail to defend the Empire, white supremacy in the Empire, and the exploitation of black labour. He was an admirer of Hitler's domestic policies, only objecting when German expansionism threatened the British Empire. His sole aim in the war - as all serious historians now agree - was to hang on to as much of the British Empire as he could.
Marx and Engels protested 'On what foundation is the present family, the bourgeois family, based? On capital, on private gain. ... real point aimed at is to do away with the status of women as mere instruments of production. '
As Home Secretary Winston Churchill instructed his police officers not to arrest protesting Suffragettes at their planned demonstration on 18 November 1913 but to beat them into submission instead, as there would be 'no public advantage' to any prosecutions. For *six hours* the great crowd of suffragettes were beaten, sexually molested, baton-charged and kicked on the ground in front of the House of Parliament on Churchill's order, on the day that became known as 'black friday'.
Marx and Engels fought against racial oppression. Winston Churchill and Martin Heidegger were both responsible officials in regimes committed to racial oppression. The contrast could not be clearer.