This reminds me of what could be considered a complementary poem/song, by John F. Kendrick:

--

Onward, Christian soldiers! Duty's way is plain:

Slay your Christian neighbors, or by them be slain.

Pulpiteers are spouting effervescent swill,

God above is calling you to rob and rape and kill,

All your acts are sanctified by the Lamb on high;

If you love the Holy Ghost, go murder, pray and die.

--

Onward, Christian soldiers, rip and tear and smite!

Let the gentle Jesus, bless your dynamite.

Splinter skulls with shrapnel, fertilize the sod;

Folks who do not speak your tongue, deserve the curse of God.

Smash the doors of every home, pretty maidens seize;

Use your might and sacred right to treat them as you please.

--

Onward, Christian soldiers! Eat and drink your fill;

Rob with bloody fingers, Christ OK's the bill.

Steal the farmer's savings, take their grain and meat;

Even though the children starve, the Saviour's bums must eat.

Burn the peasant's cottages, orphans leave bereft;

In Jehovah's holy name, wreak ruin right and left.

--

and so on: https://en.wikisource.org/wiki/Songs_of_the_Workers_(9th_edi...

> Onward, Christian soldiers, rip and tear and smite!

Doomguy feels seen. Especially since fanon has it that Doomguy is Catholic.