The most elemental answer is that the lack of privacy emboldens and empowers Big Brother. In determining that the public realm is the only realm and that individuals cannot have any semblance of privacy, Big Brother's power is unquestionable. There are no checks or limitations to it. I think that this is part of the formula that allows Big Brother to present itself as such a dominant force. There is no distinction between public and private, as it is all public. Oceanic society is geared towards one end, the subservience to Big Brother. The elimination of the private realm is something that makes this a distinct and real possibility. For example, the lack of private thoughts removes one element of individual resistance to Big Brother. The removal of any notion of relationship, sexual or emotional, between people further the withering of any resistance or any type of social solidarity that could trade off with Big Brother's absolutism. The control of private thoughts, making them public in the process, helps to ensure that there can not be any sort of activism against the Party. In this light, society is geared towards one end, which is the worship and absolute submission to Big Brother.