I think that there is some validity and some resonance to the statement. Sal and Dean do define themselves and are able to share this understanding of consciousness because of their values that reject mainstream and normative culture. Both Sal and Dean exercise preference and choices that go against the grain. In this, they find a level of friendship with one another because of what they love and in what they believe. Kerouac might be making a statement on the nature of friendship. The traditional conception of friendship is one where people align themselves outside of circumstances. Yet, Kerouac seems to be suggesting that some friendships and affinities emerge precisely because of the external reality through which individuals define themselves. Sal and Dean do a fairly good job of defining themselves in opposition to what values are stressed in society. It is here where their friendship emerges and advances. Operating outside of the standard and accepted understandings, Sal and Dean seek to broaden their friendship precisely because they are not accepted by the normative society. In this, their shared values of rejection help to actually serve as a base for their own friendship. Kerouac is suggesting that in the shared and willing rejection of standard values, new values of friendship can emerge and strengthen bonds even more.