This position is rather untenable, isn't it, as to a religionist it would be equally inconceivable and indeed offensive to undertake any public work without the invocation of the relevant God or gods?
Likewise, however, such an invocation would offend an atheist, and even, as you say, a non-interventionist deist (somehow: I'm not quite convinced that the atheist and the non-interventionist shouldn't just view it as a meaningless exercise that's more than a little humourous and leave it at that. I'm not sure where the offence really lies).
In light of that, doesn't it make the most sense to allow for a state in which the views (and I'm not suggesting this obtains presently in Canada, bear in mind) of the overwhelming majority (say a really, really Catholic country like, oh, Vatican City) are enshrined in law and practiced not simply on a private basis but in civil society and government functions, but which tolerates the freedom of conscience/thought &c. of all the citizens as private citizens?
It just seems unfair to assert that the lack of prayer, the secular position, is somehow the neutral course here, by which no one could be offended. Most well-developed moral casuistry will have some notion of peccatum omissionis, and certainly it would be thought "omiss" and grossly offensive by most of the citizenry for a state comprised mostly, but not exclusively, of religionists to neglect its God or gods at important functions of state.
Froben's comment is indicative of a certain majoritarian arrogance that I find troubling. We don't live by simple "majority rules", and the idea that a position endorsed by an overwhelming majority of the population should be the government's "official stance" is dangerous.
Canada, as a nation, does not simply "tolerate" freedom of conscience and of thought. While these are clearly foundational prerequisites for any free society, we have chosen to specifically protect certain minority rights in this country. Cultural and religious plurality are specific planks of the Canadian Charter of Rights and Freedoms.
A 2008 Canadian Press survey found that no more than 72% of Canadians profess belief in a god, while 23% are atheists. Even if all of those who believed in a god or gods could agree upon a prayer that offended none among them (surely an impossible feat, as I briefly outlined in the article above), 72% certainly does not constitute an overwhelming majority (as Froben himself indicates might be the case).
Froben says that he is "not quite convinced that the atheist and the non-interventionist shouldn't just view it as a meaningless exercise that's more than a little humourous and leave it at that". But the fact that governmental prayer is a meaningless waste of time isn't the salient point. If City Councillors routinely opened their meetings by throwing cream pies at each other (something equally ridiculous, to be sure), I would still be dismayed at the waste, but at least it wouldn't serve to further marginalize minority groups, or to endorse a specific position in a way that runs contrary to the spirit of the Charter.
And finally, I must contest Froben's premise that "to a religionist it would be equally inconceivable and indeed offensive to undertake any public work without the invocation of the relevant God or gods" on two points. First, I never suggested that prayer at public meetings should be forbidden. Far from it! I even mentioned that individual councillors should feel free to pray. However, I maintain that no prayer should be led as a part of the official proceedings. Second, it is hardly uncommon for religious people to carry out their jobs (whatever they may be) without insisting that their coworkers join them in prayer before the work day begins. Froben's assertion to the contrary is absurd.
"Secular" doesn't mean "atheist", and it isn't a dirty word. Secularism doesn't oppose religion; it simply does not address religion. Failure to endorse a specific religion at the outset of a City Council meeting is indeed the neutral course of action, as it neither affirms nor denies any religious position.