I cannot help but think it's an apples and oranges comparison.
As I recall something like 90% of the strength of a tube vs a solid is in the outer 10% of the diameter. That makes the inner hole of minimal significance on one hand. On the other hand the diameter of tube of the forged ring is significantly larger (thicker) so it would be significantly stronger than the rolled ring tested assuming the same material. He has no way of establishing that.
My bottom line is that I do not know what he was trying to prove in his climbing activities but as far as hammocks go I do not see a problem with the strength. There does seem to be a significant weight issue in favor of the rolled ring for our use. When I start seeing reports of deformed rings on a hammock I will get concerned.
Free advice worth what you paid for it. ;-)