In 1984 how does Winston Smith’s character change when O’Brien asks him to join the Brotherhood?

When O’Brien questions Winston and Julia about what they are willing to do to join the Brotherhood and fight to bring down the totalitarian regime of Big Brother, they answer that they are willing to do such things as spread venereal disease and throw sulfuric acid in a child’s face. Up until now the reader may have felt a kind of solidarity with Winston, knowing that it would not be easy to live under the thumb of the Party. The reader may even go so far as to agree that overthrowing an oppressive regime takes courage and commitment and often violence. But hearing Winston say these grisly things, his character starts to appear more barbarous and less understandable. It seems that, once Winston and Julia agree to such actions, they have already lost their humanity. They don’t need Big Brother to take it from them.