Brotherhood vs. Party.

Are winston and Julia really prepared to do all of the things they said? like throwing acid in a kid's face? it seems like they were totally into what O'brien was asking, even if those things were atrocious. were they just saying yes automatically? that doesn't seem very smart. well, neither was just going to o'brien's in the first place, I guess... I am just concerned. Is that what the brotherhood stands for? I thought only the Party would do lots of horrible things to other people . So which is better ? the party or the brotherhood? Also, Goldstein is fabricated, right? So does that mean the brotherhood is too? It really is cold, asking so much of people and then leaving them to rot in a cell, or wait to be vaporized, because of their "treachery."