I don't really understand your criticism.

I think i understand what this is about. It starts with this code (inlined for brevity)

  > QFont passwordFont = QFontDatabase::systemFont(QFontDatabase::FixedFont);

and this distinction of characteristics

  > "fixed" and "unambiguous" are different things 
  (note: there is no QFontDatabase::UnambiguousFont)

and an actual bug somewhere else as the root cause

  > broken in lubuntu 17.10: resulting font was neither fixed nor unambiguous.

which finally resulted in:

  > this kind of utility needs the option to specify a specific font

but things got heated between "not a bug: fix your system" and "this utility can be improved" ending in personal insults and everyone being annoyed by each other despite showing great love for the application (just foss things)