It is appropriate too, for Cecil Spring-Rice rewrote the first verse as "a reference to England and the sacrifice of those who died during the First World War".
Shortly before his departure from the US in January 1918, he re-wrote and renamed Urbs Dei, significantly altering the first verse to concentrate on the huge losses suffered by British soldiers during the intervening years.
I am sure that many commenters will level derision at your humble Devil, given his declarations on atheism (for the poem is about how Christians are bound to serve both country and god), and some will no doubt find its patriotism overblown and, possibly, offensive.
Ultimately, however, since one is commemorating, at least in part, those who died generations ago, I do not think that it is inappropriate to do so through a poem expressing values that they themselves would have shared (at the beginning of the wars, if not by the end).
I vow to thee, my country, all earthly things above,
Entire and whole and perfect, the service of my love;
The love that asks no question, the love that stands the test,
That lays upon the altar the dearest and the best;
The love that never falters, the love that pays the price,
The love that makes undaunted the final sacrifice.
I heard my country calling, away across the sea,
Across the waste of waters she calls and calls to me.
Her sword is girded at her side, her helmet on her head,
And round her feet are lying the dying and the dead.
I hear the noise of battle, the thunder of her guns,
I haste to thee my mother, a son among thy sons.
And there's another country, I've heard of long ago,
Most dear to them that love her, most great to them that know;
We may not count her armies, we may not see her King;
Her fortress is a faithful heart, her pride is suffering;
And soul by soul and silently her shining bounds increase,
And her ways are ways of gentleness, and all her paths are peace.
Of course, as the Royal British Legion would no doubt wish to stress, the Poppy Appeal also aims to commemorate those who have fallen in more recent wars—men whom we should honour whatever your feelings about the reasons given by politico scum who lead our country into said conflicts.
The Poppy Appeal also helps and supports the soldiers who have been injured and traumatised in said wars and who have been, mostly, abandoned by our shabby, disgusting, corrupt and amoral politicos: once again, these brave men deserve our help.
Perhaps we should get our valiant politicos to swap their pensions with those of our soldiers? I am sure, as the architects of these wars and the supporters of the shabby treatment meted out to our soldiers, that MPs would be thrilled at the idea and only too pleased to acquiesce...