The poem
Heretics all, whoever you may be, In Tarbes or Nimes, or over the sea, You never shall have good words from me. Caritas non conturbat me.
But Catholic men that live upon wine Are deep in the water, and frank, and fine; Wherever I travel I find it so, Benedicamus Domino.
On childing women that are forelorn, And men that sweat in nothing but scorn: That is on all that ever were born, Miserere Domine.
To my poor self on my deathbed, And all my dear companions dead, Because of the love that I bore them, Dona Eis Requiem.
At a glance, or by reading this the first time through, it seems very much like his other poems only warning against living as a drunkard. At further analysis, you should see the stanzas end in Latin. These stanzas form an almost subliminal message testifying the true depressing manner of this poem, and telling of the condemning poison that spirits tend to be.
Hillaire Belloc was a great Catholic writer from France. The basic "gist" of the poem was his distain for heretics (i.e. protestants) and their puritanism while Catholics can drink our wine and not be dour killjoys but our lives are also hard and thankless at times. It is not about the "evils of booze".