The excerpt is from a reply to a speech by Rudyard Kipling. Kipling had argued in this speech "An Undefended Island" that something of the fighting spirit of the English had been lost due to the loss of a certain type of man in the Great War and that there was a risk that powers like Germany and Russia would rise in strength whilst the English remained complacent.
The Spectator writer argued in response that pacifism was in line with British values:
These questions may plausibly be put, but only if those who ask them are prepared to say what ideals, other than that of peace, but in accordance with traditional British virtues, are preferable...The more closely we examine the question the more we shall find that the qualities which we prize as being characteristically British cannot readily be manifested under the conditions of war...The prospect of war...leads to a demand in each country to be self-contained, and so to economic nationalism, trade restrictions, uneconomic production, and unemployment. It involves the exclusion of aliens and restriction on travel. These various consequences condemn each nation to a too self-dependent and therefore narrow existence, cut off from healthy intimacies with other people; and the general regimentation of life which follows when a strong central authority sets itself to prepare for war and organize economic supplies leads or tends to lead to dictatorship under which freedom and tolerance disappear.
The British people are in the main pacifist by temperament not only because they dread war itself, but because they value all the things which wars and threats of war destroy. The roots of modern pacifism lie far back in the history and character of the British people...In the past they have willingly granted asylum to aliens on British soil, partly because they believed that freedom of movement and trade were profitable, but partly also because their standards of conduct were based on a conception of the personal rights of every individual as an individual, and not merely as a Briton. Citizenship of the world is a notion which can be more easily entertained by the British than by other people. The conception of citizenship which can be widened out to include the native inhabitants of countries once subject and now becoming increasingly free makes us less insular than we once were, and certainly more ready to respect citizen rights in foreign countries.
This is the mindset of classical liberalism. Note how British values are defined in terms that could only in the long run undermine Britishness: citizenship of the world, citizenship widened out to those living in former colonies; granting citizenship to asylum seekers; freedom of movement; personal rights based on every individual as an individual and not merely as a Briton etc.
It clearly had an influence among Conservative Party types and you can understand from this why Britain changed so radically after WWII.