The striking phrase is "democracy itself". Mr Colville's choice of phrasing seems to be saying that it is more important that we care about democracy than that we care about politics.
But surely the important thing is not so much the fact that we method by which we choose our government (i.e. democracy) as the quality of our government, and the actions of our rulers. One of my favorite comments on the subject is "Democracy is two foxes and a chicken deciding what to have for dinner." A government chosen by majority vote is not necessarily going to do what is good - and their track record shows that democracies often treat minorities badly.
And yet, for all that, democracy is widely treated as sacred - as something that cannot be questioned. As a Christian, I find it interesting that while the Bible has quite a lot to say about rulers and about the business of government, it never says anything that suggests that democracy might be a good idea. (And this is not simply because it would be anachronistic to do so - the New Testament was written in Greek, and most of it took place in a Greek speaking environment, several hundred years after the development of Athenian democracy. At least some of the writers of the New Testament must have been familiar with the concept of democracy.)
Christian thinkers have attempted to justify democracy. Probably the best known such justification camne from the American theologian Reinhold Niebuhr, who wrote "Man's capacity for justice makes democracy possible; but man's inclination to injustice makes democracy necessary."
I personally think that Niebuhr is correct. If there were not some sort of human capacity for justice, majorities would not respect the rights of minorities. But much more importantly, the fact that people - and, specifically, rulers - have a tendency to be unjust, means that it is very useful to have a means of getting rid of unjust rulers without bloodshed.
And that is the great thing about democracy. It is not that it enables the people to choose their own rulers - it is that it enables the people to remove their rulers from power.
It is does not do this perfectly, for quite often it simply replaces one government which serves a particular sectional interest with another government which serves the same sectional interest. In modern democracies, the vast majority of the political class, no matter what their party allegiance, often share the same values, outlook, and policies.
It is also true that, in theory, a system could be devised which would enable oppressive governments to be removed from power bloodlessly without having democracy. But I do not know of any such system ever having been implemented successfully.
in short, Winston Churchill was probably about right when he said "democracy is the worst form of government except all those other forms that have been tried from time to time."
The point is that democracy tends to serve freedom. And it is important that it is not the other way around. Freedom must be the master, democracy must be the servant. Hence I would have preferred it if Mr Colville had written "the impression seeps relentlessly through that politics, politicians, democracy and even freedom itself just aren't worth caring about." For that is what concerns me.