There is constructive criticism and there is destructive criticism. There is a time for debate on the Right and a time to either be silent or gun for Labour. At the moment there's too much ill-discipline on our side of the fence.
This close to a General Election is a time for people on the right to weigh their words carefully. Do they really want to help re-elect a government that has taken state spending to more than 50% of GDP? The Cameron-led Conservative Party isn't perfect but this election isn't a choice between a perfect and an imperfect Toryism but between Brown's big state interventionism and David Cameron's alternative.
No one has a duty to represent a political party that just happens to be broadly on the same side of the political spectrum, in fact newspaper columnists have an obligation to give their honest opinion and not simply to wave pom poms in support the blues. What does he think would happen to the credibility of someone like Peter Hitchens if after 5 years of criticising Cameron he then applauds him for 5 weeks? One of the reasons for the success of Conservative Home website is surely its independence from the party it supports, it is no different for pundits.
One of the worst aspects of US punditry is the extent to which they align with political movements, this is not something to be emulated.
As it happens I think that a David Cameron led government will be a vast improvement on one led by Gordon Brown and my vote will reflect that, but if someone doesn't believe this then it is perfectly "legitimate" to say so.