As others have said, if you passed heart phase then your group's DPS was fine.
90% of that fight is making sure you dodge everything.
If they kicked you for getting hit by too many Weight of the Land/Bombs/Landslides, then it would make sense because that severely strains healing.
If they kicked you for low dps when the group was already passing the heart phase each attempt, then they're just looking for someone to blame for their own failures.
