I think this is because on the pi people are using runcommand instead of mame directly. By default when you run "Generate romlist" for mame in attract-mode, it tries to run the configured emulator with the "-listxml" parameter, (so "mame -listxml") to get full game names. I expect this won't work with runcommand configured.
As a workaround, you can generate a mame xml file yourself outside of the frontend with the command:
mame -listxml > mame.xml
Then in the frontend's emulator configuration, put the full path to that mame.xml file into the "Additional Import File(s)" field. Attract-mode should then pick it up and use it to replace the zipfile names with the proper names when you run "Generate romlist"
I hope this helps