Why would a PODCAST (voice audio) be a recording in stereo?

You can use "lame" to down mix stereo to monophonic to cut the size of MP3 files containing voice or speeches to half the size:

  /usr/bin/lame -m s -a --quiet  ./$i /mono/$i

You could put this into a Linux or Cygwin bash script to cut down the size of the files on your hard drive, cloud drive, or other types of storage.