B'Tselem's account is as follows: they got warning at 1:30 to evacuate, they evacuated. At 2:50, a missile was fired, hitting the solar water tank on the roof. People went up to investigate, then another missile hit at 3:00 while they were on the roof. The IDF claimed that it was too late to stop the second missile, (a claim B'Tselem rejected, but that is not relevant here). This is in no way an account of human shielding. The sources you quoted were all very close in time to the attack, when things were unclear and Israel was itself either not sure, or spinning this (take your pick based on your estimate of how nefarious they are). It is not fair to present this as uncontested fact, since this is obviously a loaded accusation. As to the voluntary human shielding by activists, that should be separated out clearly, since as far as I know, nobody has died.