What do they want?

What does Emcee want? That is a question that can be left to the imagination. He doesn't share any of his real self to the audience so trying to figure out his motives has to be left to the script. I would say that he wants the audience to realise that discriminating people based on their beliefs or looks is wrong. He sings about a Gorilla in order to highlight the stupidity of the reasoning that the public have created. Realistically you would never use a Gorilla as a metaphor for who to love and who not to love. But is the most extreme of metaphors in order to demonstrate the whole concept. I think because Emcee has spent his life pleasing someone or an audience he could possibly agree with the cause he is preaching about. So if his message isn't conveyed he might give up his fantastical lifestyle as the Master of Ceremonies because all hope is lost. Or worse the audience will forget his song about loving people that different, whether they are Jewish or a Gorilla. The importance of the song at this time in history is to get the message across before the war begins and people like Fraulein Schneider are forced to choose between the person they love and the beliefs that they have. The song is performed in a light hearted way but the harsh reality of it was that it was coming true.