However, he is surely correct in the central thesis of his argument, namely:
To accept that religious views are an election issue does not mean embracing sectarianism, not does it lead to the preference of Iranian-style theocratic rather than democratic principles , as some of the more extreme critics of religion might suggest.Thus scrutiny of any politician's religious views is perfectly legitimate, and this is perhaps particularly so with regard to Mr Kerr's membership of controversial Catholic group Opus Dei - the nexus between religious precepts and practices on the one hand and politics and democracy on the other should not need spelling out, and thus the possible impact of the former on the latter deserves scrutiny, particularly where there's the possibility of inconsistency and hypocrisy.
The reason that religious views are important is that you cannot divorce one set of principles from the convictions and beliefs that shape people's thoughts in other areas too.
Therefore George W Bush's Christian fundamentalism has, of course, been rightly scrutinised, as has Tony Blair's perhaps more covert religious views, not to mention the latter's (and the likes of Anne Widdecombe's) conversion from the Anglican to Roman Catholic church. Gordon Brown's 'son of the manse' Presbyterianism has also attracted much comment, as did Ruth Kelly's membership of Opus Dei.
In the Scottish context Stagecoach mogul Brian Souter's religiously-inspired social conservatism came to public prominence when in 2000 he financed a private referendum on the promotion of homosexuality in schools, while more recently his bankrolling of the SNP's 2007 Holyrood election campaign once again brought his faith and opinions into focus. Earlier this year Muslim SNP PPC Osama Saeed's advocacy of a global caliphate for the Islamic faith attracted criticism (although his recent appearance on Newsnicht perhaps suggested that Mr Saeed is of a dangerously naive and idealistic bent that might open the door to radical Islam rather than being an Islamist himself).
Therefore it is right that Mr Kerr's religious beliefs should be examined in the context of his politics, and indeed the Souteresque association of Opus Dei with social conservatism in general and homophobia in particular seems to be at odds with the SNP's language of diversity and inclusiveness, not to mention the irony of claims that Grant Thoms withdrew from the SNP slate for the Glasgow constituency because of fears that his sexuality might be exploited. Similarly ironic is perhaps criticism of Mr Kerr supposedly downplaying Scottish sectarianism given the subsequent revelations about his Opus Dei membership. (However, all this does perhaps confirm the SNP's characterisation as a broad church(!) held together by the party's independence quest, and thus an Achilles' heel that is currently kept under wraps by recent success at the ballot box and which the opposition parties are currently failing to exploit.)
Of course, when questions of faith are raised in the political context the kneejerk response is often that the two should be kept separate and that religion is being exploited, but unfortunately that's politics, and the usual hyperbole and hypocrisy evident in this regard is no different from any other issue; it's the inevitable price of becoming involved in party politics.
Indeed, if the SNP's opponents are exploiting religion then it should go without saying that the nationalists are hardly averse to exploiting religious symbolism themselves - the Christian roots of Saint Andrew and the saltire shouldn't be forgotten in the flag waving and populism over a public holiday on November 30, for example. On the other hand, if Mr Kerr is as influential in the SNP as is being suggested then perhaps his Catholic fundamentalism was instrumental in the Scottish Government's decision not to celebrate the Reformation!
There's nothing wrong with politicians having strong religious views and allowing this to influence their stance on what others regard as secular issues, but if we are to have faith in politics then openness and scrutiny are prerequisites.