The problem of Rawlsian rational secularism is that it has been existing only for a few centuries meanwhile the other big religions I mentioned have been existing for millenniums. So, even though Rawls puts emphasis on the neutrality and the rational logic of his rational secularism, it cannot defeat the wisdom and the emotional and spiritual inspiration of these big traditional religions. Furthermore, his neutrality is questionable because how can we determine what is neutral? Then, we can see that Rawls has failed into the trap of the moral universalists' hypocrisy. Even though Rawls promotes the pluralism, his pluralism only exists under the dominance of his rational secularism, the Godless monotheism. I would rather support his disagreeing Modus-Vivendi state where none determines which religion (including the modern secularism) is the mainstream.
Unlike Rawls, I support the state of Modus Vivendi in which various believes are still confronting each other but having stopped fighting together. In Modus-Vivendi, there are two or a few more big religions are competing each other for the religious dominance. This method creates an oligopoly of religious believes rather than the monopoly by one. Thus, these groups eventually improve their belief system in order to attract more followers to join. This Modus-Vivendi situation also prevents cults which are the small religious groups. As the competition among big religious groups is already intense enough to prevent the new entrant of these cults into the market of religion, then cults will be eventually expelled out.
British Industrialisation and the development of the rest of Europe were successful due to this Modus-Vivendi state which Rawls criticised. The competition among various few big religious groups encouraged the intellectual, mental, and spiritual growth in these areas in Europe from 16th century to 19th century. I highly condemn the rise in the intense modern Western secularism in 20th century which monopolised the belief system in our world. The modern secularism should prevail if it is demanded, but it should not monopolise individuals' belief.
I believe the moral is relative across different time. place, and occasion. So, if the culture code of a civilisation requires secularism to be a secularism, then the public sphere shall be secular. The separation of Church and state is not mandate: this is the choice for a particular civilisation. So, some civilisations at a certain time period adapt (Roman or Anglo) Catholicism, Orthodox, Judaism, or Calvin or Luther Protestant as a mainstream public belief. These religions provide individual citizens with a moderate and civil religious codes.
My admiring Max Stirner, the father of individual anarchism, highly criticised (Modern Western) Secularism as a form of Monotheism. So, he warned on the danger of the modern secularism dictating individuals' belief.
Emancipation from the veil of ignorance is impossible because we human-beings are constantly suffering from ignorance. In addition, we have never known what is an ultimate right choice in our life. So then, the freedom of choice prevails. Freedom of choice gives us the chance to try finding the right way of life depending on the situation given in different time, place, and occasion. Rawlsian way of life is too restrictive to trust individuals' decision.
Rawls also ignores how individuals are motivated to live. We do not live to pursue the ultimate universal truth; We live for our reason to become happy. Regardless of the expected outcomes, we live with our own reason. Rawls is sceptical about reasons because reasons can be biased by our own subjective prejudice. But, we do neither have enough time to research about the ultimate truth nor want anyone to teach what is the absolute necessity we should pursue in our life. The world is constantly changing so that the effort of our ability is too slow to catch up with chasing the absolute truth. Hence, the ignorance always constantly haunting us.