In 1923, Hesse settled in Switzerland, where he had been living for the past ten years and remained until his death in 1962. There he adopted a stance of detachment from political struggles, which he presented as an example for Europe’s beleaguered intelligentsia. But what was the positive content of his vision, if any? Did it serve any impulse higher than an anxious need for peace and quiet? These are questions Decker does not answer. Hesse’s sheltered lifestyle could hardly serve as an inspiration for the European intellectuals to whom he directed his writings in the interwar years. Dropping out of society is impractical when society is in chaos, and barely imaginable in a totalitarian regime such as Soviet Russia or Nazi Germany. The studied impartiality Hesse adopted towards the mass movements of his time was impossible in countries where they had taken control. In reality, his pose of independence was more a psychological stratagem than a principled stance.
I think that the verb address might fit the purpose.
to whom he addressed his writings in the interwar years
I googled for "direct verb synonyms", found a thesaurus website, and "address" seemed the most fitting in the list of terms proposed by the site.
However, I found only a handful of "addressed his writings" in Google Books. An example:
Although Schroder and Frege were mathematicians writing primarily for a mathematical audience, they both attempted to reach philosophers as well, Schröder explicitly addressed his writings to both mathematicians and philosophers