A quick look makes the list of artists seem quite genuine. Oktoberklub, Ernst Busch etc are original GDR artists.
The one example you picked out here — "the people's policeman song" — is a GDR composition, obviously in this cover version format recorded by another band much later.
But it is wacky music in the original. The original is a children's song meant to guide good socialists into becoming good citizens, also played on TV when it was time for decent pre-schoolers to go to bed. Or taught in kindergartens.
This is a video of the original music: Der Volkspolizist, der es gut mit dir meint…
(Context: the linked video here matches the stop-motion animation style of the show "Unser Sandmännchen", and it is a genuine pre-1990 GDR-times/version/video. But it is a so-called (NSFW) underground porn parody, unearthed and widely publicised by the Franco-allemande TV station arte and shown in the documentary "Satirischer Knetgummi-Animationsfilm von Micha S." in: "Von Blümchensex und Knetfiguren – Pornografie Made in DDR" (src, full documentary on Youtube (starting at 33:00).). The possible 'original' for this is like other open socialist propaganda pieces — like our little sandman with the people's army – completely censored from archives that are available online. More info on that show in:
— Volker Petzold: "Das Sandmännchen. Alles über unseren Fernsehstar", Edel: Hamburg, 2009.
— Volker Petzold: "Das große Ost-West-Sandmännchenlexikon", vbb: Berlin, 2009.
The 'adult version' of that song's political theme is more pathetic overall: Lied der Volkspolizei - Song of the People's Police (East German song).
Lyrics for 'the helping friend of kids' that was the people's policeman here.
I'm standing at the sidewalk, traffic's rushing,
I'm scared to cross, I'm scared to go near!
The People's Policeman who's kind to us,
He's taking me across, he is our friend!
The cars are honking, the train is ringing!
Don't jump on the car, don't hang on to it!
The People's Policeman, who means well,
He shows us the way, for he's our friend!
I'm lost, the city is so big,
Mommy will be waiting. How will I find her?
The people's policeman who's good to us,
He will take me home. He is our friend!
And when I grow up, just so you know,
Then I'll be one of those people's policemen.
We help the people, I'm in on it,
Protect the children as the People's Police!
The original was written by Erika Hangel and Hans Naumilkat, credits would be "Uschi (3) & Der Kinderchor Des >>Edgar-André-Ensembles<<", released between 1967–1977. (On Various – AMIGA HITstory 1967 - 1977, AMIGA – 88697064852), more probably in 1972.