As I did not compile the latest jwm build I can only go on what I originally did way back when jwm was in the base.
That being noicons was purposely choosen as a compile time option, .i.e.,
--disable-icons --disable-png --disable-xpm --disable-jpeg
This was done to keep size of jwm to a minimum. However noions was not truly supported in jwm, Which I take as a bug in jwm. If you are going to offer a noicons compile time option then it should be supported throughout.
I am not a user of JWM and do not follow its development. Nor did I compile this latest version of jwm. If icons are now desired throughtout then such will need to be added in the interface files for this extension.