I guess speed can add to the damage sustained in a ground loop but, in my experiences damage has been caused by the objects and terain at the sides of the runways once directional control were lost.
I have been in a few ground loops, some as passenger and some unfortunatly at PIC.
1. At age 12, I was in the copilots seat of a Beech 18 that ground looped on take off when the right landing gear sissors failed allowing the right gear to turn to the right. We extited the grass runway facing the end of the runway where we had just started our take off roll from. Unfortunatley , there was a ditch along the side of the runway that ripped off the left landing , the wing dropped and bent as it hit the ground, The prop, which had been slowing because the pilot had yanked the throttles and mixture, hit the ground bending and slinging dirt and dust into the air. The plane was heavily damaged. If the ditch wasn't there it would have just been a wild ride with little to no damage. Our speed never got above 30mph.
2. I was in the copilots seat of a Cessna 180 with a freshly checked out low time tail wheel pilot. He performed a good landing but carried to much speed as he turned from the active runway to the cross runway on roll out. He lost control at a speed of about 10 to 15 mph. We spun around, the right wing tip came dangerously close to the ground but with no obsticles , the was no damage except to his ego. He never returned to fly for us again. Again this wa on a grass runway.
3. I had an engine failure in an Avid Flyer. I landed in the grass beside the runway. At the end of the roll out when the tail lost it's controll athourity, I started to drift to the left. I had full right rudder and full right brake but couldn't stop it from turning. the momentum had started and I was behind the power curve. I was along for the ride, only going 5 to 10 mph when the left main wheel contacted the 6" high freshly cemented taxiway edge. That spun the plane and let the tail wheel hit the curb hard enough to bend the tail post which took minor work to repair. Two things added to this accident beside my lack of flying the plane until it is tied down. This particular Avid has mechanical brakes which are uselesss and the tail wheel was free wheeling because we hadn't taken the tab out of it to make it a non full swiveling tailwheel. I also contribute some of the cause to my relaxing at the end of the roll out because I was just happy to be on the ground and in one piece, again I didn't continue to fly the plane until it was stopped. If ther wouldnt have been an obstical ther would have been no damage.
4. Same Avid, I was too stupid to lock the tail wheel after the first incident. I was letting my low time friend land from the right seat. He performed a perfect landing and I turned my head in his direction, taking my eyes off the runway, to give him praise for such a great landing during roll out. As I felt the plane turn I snapped my head forward. We were turning to the left, I jabbed the rudder and brake, we were headed for the trees along the runway, I had a split second where full throttle may have saved us but I was too slow to react. As we started to spin the left wing tip caught a small tree, we spun around and the plane tipped to the right. The tail wheel was side loaded when it hit the rough ground at the edge of the runway. The tail post and wing tip were damaged but easily repaired. My buddy was devistated, thinking it was his fault. I took full blame for this incident, I should have focused on the landing until the plane came to a complete stop. My celebration of his perfect landing, during roll out, also made him relax which contributed to the ground loop. This happened on grass at a spped less than 10 mph. Again the damage occured when we contacted the trees, if it would have been an open feild there wouldn't have been any damage.
I have learned from my mistakes. I had gotten lazy when it had come to taxing and roll out, I had let my emotions break my concentration, and I had used bad judgement letting a low time pilot land such a twichy, short coupled airplane.