"Griefing" is the act of purposefully dying in game to attempt to ruin the game as much as possible. Being bad at the game and dying is not a reportable offense, and thus not something you can report someone for "Griefing". You are report banned because you don't know how to use the report system.
It's pretty clear in this pic that these people aren't griefing, considering they have souls and are buying items. They're just losing. And losing is not a reportable offense. Go outside.