This is rather old bug and not entirely correct. Current Parole version 0.8.1 in Testing and in Stable depends on gstreamer1.0*. Support for MP3 was never in plugins-good or in plugins-bad, it was in plugins-ugly. So current version depends on gstreamer1.0-plugins-base & gstreamer1.0-plugins-good, leaving gstreamer1.0-plugins-bad & gstreamer1.0-plugins-ugly in the "suggests" section. Install what it suggests to get MP3 support. Those plugins have this bad name for a reason, and for the same reason they were not installed by default.
I vote for closing this bug as not relevant. Although I haven't checked what's happening in Experimental with Parole version 0.9.2. Karolis M.
