I found four members of the chorus, including one (Coleridge) from whom I would have expected a more insightful response.
There are few instances (notwithstanding his tremendous denunciations against bodies of men, the inhabitants of whole cities or states) in which Dante forgets courtesy towards individual sufferers; and, in general, he expresses the most honourable sympathy towards his very enemies, when he finds them such. In the case of Bocca degli Abati, who, at the battle of Monte Aperto, traitorously smote off the right hand of the Florentine standard-bearer, the patriotic poet shows no mercy; but having accidentally kicked him in the face as he stood wedged up to the chin in ice, he afterwards tears the locks from the wretch’s head to make him tell his name;—forgetting, by the way, that in every other case the spirits were intangible by him, though they appeared to be bodily tormented. And towards the friar Alberigo de’ Manfredi, who, having quarrelled with some of his brethren, under pretence of desiring to be reconciled, invited them and others to a feast, towards the conclusion of which, at the signal of the fruit being brought in, a band of hired assassins rushed upon the guests and murdered the selected victims on the spot; whence arose a saying, when a person had been stabbed, that he had been served with some of Alberigo’s fruit:—towards this wretch Dante (by an ambiguous oath and promise to relieve him from a crust of tears which had been frozen like a mask over his face), having obtained his name, behaves with deliberate inhumanity, leaving him as he found him, with this cool excuse,—“E cortesia fu lui esser villano.” “’Twas courtesy to play the knave to him.”
Dionysius Lardner (1835). Lives of Eminent Literary and Scientific Men, pp. 50–51. London: Longman.
On behalf of Dante’s wife I must add that marks of a harsh temper in the author of the Inferno seem to me plainly discernible in the Poem itself. His behaviour to Alberigo in the third sphere of the last circle was worthy of the place and unworthy of a gentleman. Milton would not have suffered one of his Fallen Angels to behave so unhandsomely in the “heart of hell,” or so to forget the “imperial palace whence they came.” If it were true that brutality to one in bale† was good manners—cortesia fu lui esser villano—(which I deny, in such a case as this, where no ideal child of perdition, or abstraction of wickedness was exhibited, but a certain sinful suffering fellow creature,)—by what alchemy was false swearing and deceit rectified into righteous dealing? “May I go to the bottom of the ice myself,” said he, “if I don’t free thine eyes!” Yet after hearing his story went and left them cased in crystal! Here was the spirit that christens falsehood and ferocity by the name of religious zeal and strictness.
Samuel Taylor Coleridge (1847). Biographia Literaria, or, Biographical Sketches of My Literary Life and Opinions, volume I, part II, p. 345. London: William Pickering.
† “bale, n. 2. suffering, torment, pain, woe.” (OED)
Some admirers of Dante may be angry with me for speaking of him in this tone, but what have they to say to his treatment of Alberigo? Alberigo had his eyes fastened up with frozen tears, and piteously implored Dante to remove the ice, and so relieve him. Dante, in reply, solemnly promised to do so, on condition that Alberigo would tell him who he was, clenching his promise by an imprecation of eternal punishment on himself in case of non-fulfilment (quite equivalent to an oath, which is nothing more). “If I don’t relieve you may I go to the bottom of the ice!”
Having confidence in this most solemn assurance, Alberigo tells Dante what he desires to know, and, having told him, again begs him to open his eyes. Dante does nothing of the kind, and glories in his breach of faith.
Here is a pretty combination of cruelty and bad faith! If this is to be taken as an example of Dante’s famous “tenderness,” his tender mercies were cruel.
Philip Gilbert Hamilton (1864). ‘Gustave Doré’. In The Fine Arts Quarterly Review, October 1864, pp. 9–10.
Such is the somewhat long, confiding talk of Friar Alberigo, who now prays: “Reach hither and open my eyes.” But what does Dante to the poor wretch? He refuses the simple, easy relief, after he had promised it and obtained the reward of his promise: “And I opened them not, for to be rude to him was courtesy.” Yet a far deeper violation than that of courtesy was here; charity was wronged, humanity, in the person of the miserable, suffering sinner. […]
O Dante, thou didst here turn a demon thyself, a very devil to that wretched sinner, torturing him with treachery, whereby thou wert too a traitor. No fiends, Malacoda, Malebranche, or the rest were ever guilty of greater fraud than thine, and surely thou hast thyself been immered in ice; not only “has all feeling gone from thy face,” but all pity from thy heart—nay, truth has departed from thy conscience. A frozen soul thou art, here in the realm of frost; there is no justifying that falsehood by any account of “righteous indignation;” by thine own word and proof thou art a liar. Repeatedly hast thou demonized thyself in this Inferno; far up yonder thou didst begin with Filippo Argenti in a sudden tumult of wrath; but here thou art the worst, here at the bottom thou hast grown in demonism with Hell itself, in this Circle treacherous with the traitors.
Denton J. Snider (1892). Dante’s Inferno: a Commentary, p. 456–457. St Louis: Sigma.
I think Snider meant to be snide when he said that Dante has a “sudden tumult of wrath” in the circle of the wrathful, and is “treacherous with the traitors”, but if only he had left off the sermonizing he might have realised he had recognized the poet’s design.