I'll start by dealing with Mr. Cameron's speech first, mainly because it's the sanest and does express some subtlety before delving briefly into Sen. Bernadi's racist rant.
Mr. Cameron's main thrust is that the "soft" left's articulation of the causes of extremism is incorrect and the soft left position has resulted in a "passively tolerant society [that] says to its citizens, as long as you obey the law we will just leave you alone", which has led in turn to segregation and isolationism encouraged by State multiculturalism. Mr. Cameron's argument is that society needs to champion liberal democratic "values" as part of a national identity.
The funny thing is, this is just the sort of thing that some in the Left have been arguing for years. Cameron accuses the supporters of multiculturalism of preventing debate on issues and hampering efforts to confront some of the egregious cultural practices and beliefs in some communities.
According to Cameron:
"when a white person holds objectionable views, racist views for instance, we rightly condemn them. But when equally unacceptable views or practices come from someone who isn’t white, we’ve been too cautious frankly – frankly, even fearful – to stand up to them."This is, of course, the sort of complete bollocks that the Right loves to trot out - it's actually the articulate way of expressing the Bogan battlecry "political correctness gone mad".
The problem is that when the Left argues for a particular liberal value, the argument is often articulated in a universal way. For example: "sexism, in all its forms, is unacceptable". Its never articulated with the provsio "unless its OK in X culture" - however this is just what Cameron is accusing.
The Right, however, has no problem in doing exactly the same thing - playing a bit o' relativism. Confronting sexism in a cultural group is admirable to the Right because "they treat women badly in their culture", however universalising the value to apply to everyone (for example, policies to combat sexism in the workplace) is "political correctness gone mad" because hey, the boys were just joking...right?
So which liberal "values" are we really championing here? It sounds like the sort of relativsim that comes out the "clash of civilisations" ideology, ie. that a particular culture is unable to incorporate liberal values.
Which brings me away from Cameron's more reasonable argument to Sen. Bernardi's rant.
Bernardi argues that the multicultural acceptance of Islam "has resulted in a cultural clash that has brought almost unprecedented levels of social unrest ". Further arguing that Muslims cannot be integrated into a liberal democratic culture - even going so far as to quote that paragon of liberal values and tolerance Lee Kwan Yu.
Sen. Bernadi agues that Australia must do something before its "too late" but nowhere in his rant does Sen. Bernardi propose any solution. Which makes one wonder, if Islam is impossible to integrate and as dangerous as Berardi suggests what could possibly be the solution to them living within our midst? For fear of Godwin's Law I won't continue to speculate.
Ultimately this debate from Cameron and Bernardi is a cheap resort to petty Nationalism in the guise of liberal "values". There is nothing wrong with championing liberal values in society to combat extremism, in fact, its admirable. However, the Right has to understand that this means applying those values universally to our own culture as well as to other cultural groups within our society - without the incessant yells of "political correctness". The universal application of these values is what will construct a truly liberal democratic, multicultural society rather than pandering to petty Nationalism to undermine multiculturalism as a policy.