Earlier quoted context omitted.
George Orwell was against all kinds of authoritarianism. A large portion of the left has always disavowed authoritarianism as well, so there is no conflict here.
'George Orwell' is a fictional character. Real name: 'Eric Blair' who went to Church every Sunday, though I think he was kind of an Atheist. Not the same dude as Orwell. He had complicated views, and was not a 'socialist' in the more popular sense. Remember in 1984 that the 'bad guys' ideology is 'IngSoc', i.e. 'English Socialism'. So not exactly a big Social Dem supporter of the era.
I don't think this is complicated; in-fighting amongst left-wing/socialist groups is a staple ever since the term was coined. Socialism never had a single main ideology.