Mouin Sent me this: "I was about to send you the Roth quote regarding sourcing from Beirut but you had already posted it.
Regarding the question you pose at the end, he has in fact already answered it:
"As part of its response [to Israel's Operation Cast Lead], the organization simply feigned ignorance. “Israel's refusal to grant access to Gaza for all international media and human rights monitors since the fighting began on December 27”, it complained on 12 January, “has limited severely the flow of information and investigation from impartial observers into events on the ground”. “Human Rights Watch,” it had the cheek to report on 16 January, “is unable to conduct full investigations into alleged laws of war violations by either side because of Israel's continuing denial of access to Gaza”. This despite the fact that the Gaza Strip was saturated with Arab journalists, local and international humanitarian staff, medical personnel including several Europeans, and approximately 1.5 million residents most of whom had at least intermittent access to telecommunications. Yet none of these, apparently, met the criteria of credible witness. Indeed, HRW’s main and almost exclusive source of reliable information consisted of staff located on the Israeli side of the boundary on account of Israel and Egypt’s ban on entry to the Gaza Strip."
