Horrifying, disgusting, disturbing and funny all at once

I've been reading James Joyce's A Portrait of the Artist as a Young Man. It's incredibly good, much better than I expected.

Today I read JJ's recount of a priest's lecture about Hell and judgment given to a group of young Catholic schoolboys on "retreat." This bit goes for pages, but it's loaded with brilliant bits. This one stood out for me. It made me cringe and laugh (out loud.)

The horror of this strait and dark prison is increased by its awful stench. All the filth of the world, all the offal and scum of the world, we are told, shall run there as to a vast reeking sewer when the terrible conflagration of the last day has purged the world. The brimstone too which burns there in such prodigious quantity fills all hell with its intolerable stench: and the bodies of the damned themselves exhale such a pestilential odour that as saint Bonaventure says, one of them alone would suffice to infect the whole world. The very air of this world, that pure element, becomes foul and un-breathable when it has been long enclosed. Consider then what must be the foulness of the air of hell. Imagine some foul and putrid corpse that has lain rotting and decomposing in the grave, a jellylike mass of liquid corruption. Imagine such a corpse prey to flames, devoured by the fire of burning brimstone and giving off dense choking fumes of nauseous loathsome decomposition. And then image this sickening stench , multiplied a million fold and a million fold again from the millions upon millions of fetid carcasses massed together in the reeking darkness, a huge and rotting human fungus. Imagine this and you will have some idea of the horror of the stench of hell.

I wish I knew why that made me laugh because I don't think it was intended to be funny, at least not in the context of the story.