In the same vein as the poster above, the standards of practicing medicine are not equal across borders. That's why a doctor in country A might not be able to practice in country B without obtaining the requisite licenses to practice. Countries that have lower barriers to entry to practice medicine and poorer sanitation standards for their facilities, and generally higher rates of complications should be approached with the appropriate level of caution.
Given that I don't know the details of this particular complication, it wouldn't make sense to discredit any Dr. because of a single complication. Surgery comes with complications, and if every surgeon was dinged for every mishap, we wouldn't have any trust worthy surgeons. The best way to get 0 complications is to not practice at all! However, if there's evidence for a pattern of negligence, then you may have a point.
To add on to that, based solely on the Xrays, other highly regarded doctors mentioned that they would have made the same call (i.e. to remove the nails). I do sympathize with the patient for his experience though. Without knowing too much, I am angry at the way he was treated. At the same time, we don't know Dr. D's side of the story either (he could have been dealing with a patient who was doing even worse as hard as it is to imagine, or he may have been in surgery at the time). Until we have all the details, it's best not to jump to any conclusions.
Personally, I would be more cautious when dealing with Dr. D after this incident until the full details are revealed, but I think it's in poor taste to try and discredit him at this stage.