Hubert Schölnast has explained why the weird phrase "verantwortetes Hohnlachen" should be regarded as an idiosyncrasy of the author.
Anyway, the verb veranworten also has another connotation than "responsible for". This may be outdated nowadays, but perhaps it was not when the author wrote his text (or the author had a fondness for old-...
Früher (bis ins 17. Jahrhundert hinein) wurde das Verb mahlen stark (unregelmäßig) konjugiert (ähnlich wie fahren oder tragen):
Ich mahle Weizen zu Mehl.
Du mählst Weizen zu Mehl.
Der Müller mählt Weizen zu Mehl.
Gestern muhl ich Weizen zu Mehl.
Weizen wird zu Mehl gemahlen.
Das hat sich dann geändert, und heute ist mahlen ein schwaches (regelmäßiges) Verb ...
You found out about the so called Nominalisierung:
Nominalisierung means: In German you can build a noun from about every verb by just adding an article and writing it with a capital letter:
Ich schwimme - das Schwimmen
Du fährst - das Fahren
Er singt - das Singen
If you take the verb in its participle 2 Form, then it stands for the object of the action. ...
"Verantwortet" as "gerechtfertigt" or "berechtigt"
None of the comments or answers so far (even PaulFrost's interesting deep dive into the DWB) has attempted to clarify what meaning the author, Peter Altenberg, usually attached to the term "verantworten".
This can be done by way a corpus search: the 1919 collection ...
Better you don't try to copy grammatical features from one language to another. Better you try to learn to use a new language like native speakers. No German native speaker has English Grammar in their mind when they produce German sentences.
The two German sentences in your questions are correct, but unusual. German native speakers normally don't use such ...
Normal participle clauses
German participle clauses work pretty much the same way as in English, which is not surprising since the two languages are closely related.
So the participle clauses you were not sure about can be easily translated into German participle clauses:
Besorgt über die Neuigkeiten rief sie das Spital an. (Worried by the news, she called ...
Here are some translations that are close to the original.
"Worried by the news, she called the hospital."
"(Von den Nachrichten) besorgt rief sie im Krankenhaus an." or "Besorgt (durch die Nachrichten) rief sie im Krankenhaus an."
Although, if somebody told her the news personally, you would probably leave out the parts in the ...
It's just an error in the subtitles of the video.
In the audio, the moderator (correctly) says:
...und sie sind innen gefüttert mit einem Fell.
The subtitles have the additional (incorrect) word "hat". There's a correction notice in the video description on YouTube.
The versions you propose in the question are also correct and natural. "...
Peter Altenberg speaks in this text from an event in the year 1918 in past tense:
Im Jahre 1918 glitt ich von der schlecht von Seife abgeschwabten Steinstiege vor meiner Hoteltüre mit meinen glatten Holzsandalen, nachts 1/2 12 Uhr, nach rückwärts aus, brach die beiden Handwurzel-Knochen.
But Altenberg died of pneumonia on 9th of January 1919. This means, ...
Yes, your analysis of "zum bestandenen Examen" is correct. It's like "post christum natum" in latin.
The sentence is missing a predicate and an object, one way to complete it would be:
Ich habe mir zum bestandenen Examen etwas geschenkt.
You are right, the grammar is miserable. As the comments say, the simple reason for the misuse is that the verses form a rhyme. You will also notice that some unnessary words are included to achieve that the verses have a nice meter.
Perhaps the best explanation for this phenomenon is the poem "Das ästhetische Wiesel" by Christian Morgenstern from ...