Here in the US such a report is part of our system of justice. A group of people hear accounts of what happened and make a report of the charges made. This is referred to a jury or some other body for their deliberation. No corroboration is made or even needed, since it is not a judicial finding, but just (as Goldstone) a synopsis of the charges made for someone else to consider. As to the events you mention in other countries, do things done elsewhere excuse crimes by Israel?
12 killed in Mumbai, India after building collapses during heavy rain (AP)
from the article: Goldstone to attend grandson's bar mitzvah as Zionist groups end feud