Why was the song “Mack the Knife” popular when it doesn’t make any sense?

The song ‘Mack the Knife’ has been butchered, like the titular character’s victims, until it no longer resembles its original incarnation—in which it made perfect sense.
We’re going to need to review its history a little, because most people have never, ever heard the original version of ‘Mack the Knife’.

The song originated in Kurt Weill and Bertolt Brecht’s 1928 play with music Die Dreigroschenoper (‘The Threepenny Opera’.) It’s sung by a character, the Street Singer, at the very beginning of the show.
The original version is called ‘Die Moritat von Mackie Messer’, and it’s a murder ballad about the principal character of the show, Macheath, whose nickname ‘Mackie Messer’ literally means ‘Mack the Knife’. The song is only in there because in the original production, the actor playing Macheath, Harald Paulsen, demanded that his character be given a proper introduction.
Here’s the original German text:
Und der Haifisch, der hat Zähne
Und die trägt er im Gesicht
Und Macheath, der hat ein Messer,
Doch das Messer sieht man nicht.
Und es sind des Haifischs Flossen
Rot wenn dieser Blut vergießt.
Mackie Messer trägt ’nen Handschuh
Drauf man keine Untat liest.
An der Themse grünem Wasser
Fallen plötzlich Leute um.
Es ist weder Pest noch Cholera
Doch es heißt: Mackie geht um.
An ‘nem schönen blauen Sonntag
Liegt ein toter Mann am Strand
Und ein Mensch geht um die Ecke
Den man Mackie Messer nennt.
Und Schmul Meier bleibt verschwunden
Und so mancher reiche Mann
Und sein Geld hat Mackie Messer
Dem man nichts beweisen kann.
Jenny Towler ward gefunden
Mit ’nem Messer in der Brust
Und am Kai geht Mackie Messer
Der von allem nichts gewußt.
Wo ist Alfons Glite, der Fuhrherr?
Kommt das je ans Sonnenlicht?
Wer es immer wissen könnte,
Mackie Messer weiß es nicht.
Und das große Feuer in Soho
Sieben Kinder und ein Greis
In der Menge Mackie Messer, den
Man nichts fragt und der nichts weiß.
Und die minderjährige Witwe
Deren Namen jeder weiß
Wachte auf und war geschändet
Mackie, welches war dein Preis?
For the benefit of people who don’t know German—which I’m guessing is most readers—and with the help of the version at https://lyricstranslate.com/en/die-moritat-von-mackie-messer-ballad-mack-knife.html , here’s a version in English, lightly corrected by me for intelligibility. This is not meant to be a singable version, just a literal rendering of the meaning:
And the shark, he has teeth;
he wears them in his face.
And Macheath, he has a knife,
but no one sees the knife.
And the shark’s fins are
red when he sheds blood;
Mack the Knife wears a glove
on which no one can see any sign of a crime.
By the green waters of the Thames
suddenly people drop down.
It is neither plague nor cholera,
it’s said: Mack’s around.
On a beautiful, blue-skied Sunday
a dead man lies on the Strand
and someone turns the corner,
the one they call Mack the Knife.
And Schmul Meier’s still not been found,
like many such a rich man,
and Mack the Knife has his money,
but no one can prove anything against him.
Jenny Towler was found
with a knife in her chest
and on the embankment there’s Mack the Knife,
who knows nothing about any of it.
Where is Alfons Glite, the cab driver?
Will he ever see sunlight again?
Whoever could know,
Mack the Knife has no idea.
And the great fire in Soho,
seven children and an old man.
In the crowd Mack the Knife, who
Isn’t asked, and knows nothing.
And the underage widow,
whose name everyone knows,
woke up and was defiled.
Mack, what was your price?
So, you get the idea: Macheath is a powerful and notorious criminal, and nobody can pin anything on him. The song is basically an account of his probable victims, and fits the format of your standard murder ballad.

So, the US premiere of The Threepenny Opera was in 1933, and the show didn’t exactly set the town on fire. It didn’t become popular in the USA until 1952, when Leonard Bernstein conducted a version with lyrics translated by the composer Marc Blitzstein.
This transferred to Off-Broadway in 1954, and helped make an American star of Weill’s wife Lotte Lenya, who played Jenny, and who had also played Jenny in the original Berlin production in 1928, 26 years earlier. Lenya won a Tony for her performance in the English-language version.
The original orchestration for ‘Moritat von Mackie Messer’ is sparse, and it’s played as a rather sombre walking pace, but in the US it tended to get played as a swing tune. In 1955, Louis Armstrong did a cover of it where he omitted a lot of the verses about, yunno, murder and rape—although Armstrong was attracted to the song precisely because, as he said, ‘ I knew cats like this in New Orleans. Every one of them, they’d stick a knife into you without blinking an eye. ’ Nevertheless, he inserted new verses which made Mack into less of a brutal criminal and more of a swingin’ dude:
Yeah Louie Miller, disappeared, dear
After drawing out his cash
And MacHeath spends like a sailor
Did our boy do somethin’ rash?
Sukey Tawdry, Jenny Diver
Lotte Lenya, Sweet Lucy Brown
Yes, the line forms on the right, dears
Now that Mack, he’s back in town
Bobby Darin’s hit version followed the Armstrong format, leaving out the rape and death (well, some of it) and playing up the roguish side of Macheath’s personality.
In 1960, Ella Fitzgerald was covering the song in a concert in Berlin and, after the first verse, she forgot the lyrics. So she winged it:
Oh what’s the next chorus, to this song, now
This is the one, now I don’t know
But it was a swinging tune and it’s a hit tune
So we tried to do Mack the Knife
Ah, Louis Miller, oh, something about cash
Yeah, Miller, he was spending that trash
And Macheath dear, he spends like a sailor
Tell me, tell me, tell me could that boy do, something rash?
Oh Bobby Darin and Louis Armstrong
They made a record, oh but they did
And now Ella, Ella, and her fellas
We’re making a wreck, what a wreck of Mack the Knife
Nevertheless, Ella in Berlin: Mack the Knife won a Grammy, and started the practice among performers of the song, of cheerfully making up new verses on the spot that referred to previous performances of it.
By the time Frank Sinatra got around to covering the song, it had become a full-blown celebrity namecheck-fest, in which he would usually take the opportunity to name the members of his band:
Ah, old Satchmo, Louis Armstrong, Bobby Darin
They did this song nice, Lady Ella too
They all sang it, with so much feeling
That Old Blue Eyes, he ain’t gonna add nothing new
But with Quincy’s big band, right behind me
Swinging hard, Jack, I know I can’t lose
When I tell you, all about Mack the Knife babe
It’s an offer, you can never refuse
We got George Benson, we got Newman & Foster
We got the Brecker Brothers, and Hampton’s bringing up the rear
All these bad cats, and more, are in the band now
They make the greatest sounds, you ever gonna hear
And that’s how ‘Mack the Knife’ went from being a pastiche of a murder ballad, to being a song full of references to people the listener hasn’t heard of.
Sources:
When Satchmo Covered Mack the Knife | uDiscover
The Life of a Song: ‘Mack the Knife’
Edit:
If you want to know roughly what it sounded like in the original performance, here’s a recording of it from 1929, sung by its original lyricist, Bertolt Brecht:

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