The question of whether to use das Haar or die Haare has been asked several times on this group, with a variety of different and informative answers. Here I want to ask about something that might be simply a trivial matter of style, or something more important ... (unfortunately, for a non-native speaker, it's not obvious which!)
The Goethe Zertifikat A1 Wortliste includes the following two sentences:
Sie hat lange Haare. ... given as the example sentence for das Haar
Ricardo hat kurzes Haar. ... given as the example sentence for kurz
Has either the choice of adjective (lang, kurz), or the gender of the subject, influenced the choice of whether to use Haar or Haare, or was it purely a matter of variety and style?