The best humour is offensive...
One picture is worth a thousand words. Sometimes stating that a person is crazy, by means of my crazy robot image, is the only worthy response. How can you respond to a person who equates feminism with Islam and Marxism in what is obviously an irrational statement.
If he had said that 2+2= 5 then you can have a rational discussion over what it really is. However, if he says that 2+2=oranges then there is no meaningful response possible.