When determining how to uninstall a program you need to first test it at the cmd prompt on the target computer WITHOUT using BatchPatch. This way you can determine what the quiet/silent/unattended parameter is.
I just installed FeedReader 3.14 and tested uninstalling with your commands:
“C:Program Files (x86)FeedReader30unins000.exe” /S
“C:Program Files (x86)FeedReader30unins000.exe”
Neither of those commands will perform a silent/quiet/unattended uninstall.
However, the following command works properly to perform a quiet/silent/unattended uninstallation of FeedReader 3.14:
“C:Program Files (x86)FeedReader30unins000.exe” /silent