One of the most glaringly obvious failings of Rawls was to have a liberalism so pluralistic that to stop conspiracy theorists, nationalists, pseudoscientists, and the rest, we have to wait until they have gained more than enough of a following to do real damage. Eventually, the followers may do something violent after which our Rawlsian legal system can stop them, in part, and anemically. To curtail them does not mean to outlaw them but to use soft and institutional means to censor and marginalize them.
It is not just that these movements tend to be illiberal, themselves. In religious studies, up and coming spiritual traditions are called “New Religious Movements” and there is a liberal desire to end stigma against them since they were formerly called, mostly, “cults”. Yeah, but, these groups are, more often than not, led by charasmatic authoritarians and even if that element is diminished, something they are selling contradicts science, liberal democracy, or decency.
Outside of the illiberal and anti-scientific tendencies of these movements, fringe movements tend to not provide their members with eudemonia. And, morally, I consider eudemonia a human right. If they’re raising children with only a feeble education and even deny their adults access to art, science, and metaphorical sunlight, they are then denied the fullness of humanity. Internal to these groups, homeschooling and schooling within their myopic institutions cannot lend itself to eudemonia because the teachers aren’t experts. The adults often don’t know more than the children about the subjects they’re teaching and the quality of the education is vastly reduced.
As a Nicene, trinitarian, Christian, I cherish and relish the religious diversity of the world and give my full respect to people as disparate as Mahayana Buddhists to Sunni Muslims to Conservative Jews but the smaller and newer religious, semi-religious, and pseudo-religious movements, I afford much less respect to. If someone claims to be the Madhi, the second coming of Christ, the next avatar of Vishnu, then I am deeply concerned. There is something to be said for applying the 19th century Great State theory that created the Concert of Europe to ideologies.
The big religions are big enough that they don’t need to keep their adherents sheltered from the world. People remain in them under cultural influence. As a religious person, myself, I should afford some credit to God in that; but that would be beside the point and a theological rabbit hole. My issue is not with religions I don’t believe in but with any fringe movement that is illiberal, anti-science, and contrary to eudemonia. The newer and smaller movements tend to be those things.
The major religions and secular humanism have real philosophical differences but, for daily life, they have similiar guidelines and for moral guidance, filling the psychological and social role of religion in someone’s life, and providing a community and community institution for people to belong to they all work. The secular humanists may need to marry themselves more closely to the Unitirian Universalists who are the largest secular religion. As far as pseudoscience movements, that should be replaced by real science; whatever an herb can do, a chemical can do better. I take the same approach to politics.
My politics may be closer to the Green Party or the Socialist Party but I’m going to be on the left side of the Democratic Party in America, I’d on the left side of the Liberal Party in Canada and would not join the NDP, and I’d be on the left side of Labour in the UK. Not only because it is more practical but because it lends itself to more sanity. In the words of my fellow Christian socialist, Rudi Dutschke, progress should be a long march through established institutions. If it is too hasty or too small, it may become crazy in a bad way.