In applying such rules, [they] ... must recognize possible conflicts between what is in their own interest and what is just. Only in a community of beings capable of self-restricting moral judgments can the concept of a right be correctly invoked."
The passage argues that for the concept of "right" to be meaningful, there must be a community capable of making independent moral judgments.  This implies that individual self-regulation is essential for ethical decision-making and the recognition of rights.