The problem is of course that people don't always view their differences as abuses, or share the foundational concepts that might create common ground for recognition of abuses.... My reading of Stephen is that he would disagree and hold that these rights and freedoms are primary and that multiculturalism as he understands it and defends it is in agreement. That is a position I can find little to no fault with.Not exactly.
I personally believe that these freedoms and rights are foundational. But my personal view does not carry the day in a multicultural society (nor, indeed, does anyone else's). Rather, what happens is that my personal view, along with that of many others, becomes a matter for discussion and negotiation.
Our rights and freedoms are neither inherent nor inalienable. The proof of this is the millions of people who are forced to live without them in repressive regimes. Or the ease with which they are disregarded on 'private' property such as malls, or in the workplace, or in schools. The existence and potection of our rights and freedoms is a social construct, an artifact created by society for the preservation of society.
Hence the nature and extent of these rights and freedoms is the subject of a coinstant negotiation between members of the society. The rules under which this negotiation takes place - nominally, a constitution - is established so as to create a balance between varying parties, both in the majority and the minority, to ensure that the mere (and often capricious) will of the majority does not aribitrarily extinguish those rights. The negotiation, because it is constant and ongoing, ensures that the debates are focused at the 'edges' - the points of disagreement that are typically minor, but serve as indicators for deeper divisions.
This is why no right is absolute. Freedom of speech is reigned by common sense (no shouting 'fire' in a movie theatre), consideration for others (no off-colour jokes) and legislation (no slander, defamation, no disclosure of national secrets). A society that embraces multiculturalism will typically exhibit sanctions of some sort against hate speech, or speech that fosters and encourages acts of discrimination or violence against a minority (which, when you think about it, is in force and nature indistinct from legislation prohibiting threats against the person of the President, or prohibitions banning 'incitement to riot'). The purpose of such legislation, though, isn't some sort of social engineering - it is to ensure the security and safety of all members of society.
That said, even the safety and security of all members of society is not sacrosanct. It, too, is a matter for negotiation. People engaged in dangerous activities are not guaranteed safety and security. People who break the law, and do so in a violent fashion, may be treated with deadly force. Some societies (happily, very few) even sanction the state-sponsored execution of its citizens. Additionally, safety and security is interpreted in some societies, as in Canada, to include medical care, while in others, this is not considered a social goal, and is left to private enterprise.
In general, though, what seems to have been found in practice is that societies that recognize and protect the rights of individuals, usually interpreted as the basic freedoms (of speech, of the press, of assembly, of association, of religion, of movement) and the basic rights (to safety and security, to autonomy, to ownership or property, to sustinence, to information or education) tend to be more stable than those that don't. The denial of a freedom or a security is usually grounds, eventually, for a civil insurrection (or requires a use of social force deemed intolerable by the rest of society). This is why the substantial majority in a multicultural society, once order and stability is established, recognize the value of protecting and preserving these rights.