There are three oxymorons in "1984" by George Orwell. Freedom=slavery, war=love, and ignorance=strength. What do they mean?

These specific examples from 1984 are examples of the theme of the work, namely dictatorship and totalitarianism masking in the guise of democracy.

1984, as many of Orwell's works were, is an attack on the abuse of power and how the end justifies the means.

Orwell was a committed socialist. He fought on the Republican side in the Spanish Civil War and works such as 1984 and Animal Farm are attacks on Stalinism and the abuse of power, not socialism.

Revolutions such as the Russian revolution of 1917 start out as genuine attempts to overthrow dictatorships and tyranny. However they are hi-jacked by people such as Stalin who justify their totalitarian policies in the name of the proletariat.

Therefore these oxymorons reflect Stalinist thinking whereby the masses must be guided and controlled by the state.

To take each in turn freedom=slavery means that freedom is an illusion. It is in reality a con by systems such as democracy. So freedom is really another form of exploitation or slavery. Only the state can provide real freedom.

Similarly war=love is a similar contradiction. Only through war and conflict can the masses achieve genuine power and freedom. Therefore war is equated with love in that war and conflict is a form of love for certain social classes.

Finally ignorance=strength, means that the state needs to control information. Ignorance benefits the masses because they know only what they need to know. The state will determine what information is accessible on behalf of the masses.