What he means by the veil of ignorance is that, for the purpose of his thought experiment, the hypothetical person wouldn't know what class they would belong to or what their economic situation would be. If they were placed in that situation, and asked to design the ideal society that would be suited to their needs, Rawls argues that they would always choose to create a society that looked after the least fortunate, because they were as likely to wind up in that group as in any other. Rawls's point was to provide a rational, social contractarian basis for a just and equitable society. So the idea of a veil of ignorance was essential to his argument. It seems that what you are saying is that self-interest, which is based on class and economic situation, is inseparable from one's view of the best possible society, and that is a fairly common critique of Rawls's theory.