The author:
https://en.m.wikipedia.org/wiki/Michael_HuemerSeems like a very nice argument when isolated away from reality. Reality of mass immigration from Muslim countries into the UK has been a lot more people in the UK support Sharia law and want to ban homosexuality.
https://www.theguardian.com/uk-news/2016/apr/11/british-musl...
I like libertarians, but there are some feedback loops that prevent me from universally embracing libertarianism.
Also, the author describes this right to immigrate from the context of "normal" immigrants. What is normal and who gets to define it? Seems like a fluid definition that evolves as a function of past immigration. For example, parts of Sharia law might fit in OK (usury, for example) with Western values, so maybe we let that slide for a bit. Then, after a few decades and more norming of other aspects, all these other social values become part of a voting block and get pushed into action. I don't see great examples of government in the middle East, so why would I want to normalize those social values and evolve my government to suit?
I don't consider myself anti-Islam (just anti fundamentalists, including Judeo-Christian sects) and I know a ton of secular Muslims with my values (most don't want open door immigration either!).
In thirty years of traveling to Europe to visit family, I just don't look at how they've managed immigration with a lot of enthusiasm. Nor do I want to replicate those policies here.