On 8 November 18 Palestinians were killed in Beit Hanoun Gaza when an Israeli artillary shell misfired into an apartment block. Although dozens of Qassam missiles had been fired from the immediate vacinity into Israel (and these had resulted in two civilian deaths and several injuries in Sderot in Israel) the Israelis apologised for the accident. Nevertheless the story was headline news on every media outlet for two days, and the screens were filled with the sight of dead and mourning Palestinians. The Israelis were not only condemned in the UN, but the UN has actually set up an international enquiry into what happened.
On 11 December 4 Palestinians including 3 children (aged between 6 and 10) of the intelligence officer Baha Balousheh (a loyalist of Abbas' Fatah movement) were killed deliberately in cold blood by Hamas gunmen in Gaza City. The story got barely any mention on any UK media outlet, and there were no screenings of dead and mourning Palestinians. There has been no condemnation of the Hamas Government and no mention of the event at the UN. At the moment (just 12 hours after the attack) the BBC News website has removed all references to the attack, although if you dig down you can find a video titled "three children killed in Gaza". The video makes no mention of the fact that Balousheh had been a long term target of Hamas. On the contrary the commentator tried ot make out that the whole thing was some kind of a 'mistake' and that nobody knows who is to blame (even leaving open the possibility it was the Israelis), while stating that Hamas has vigorously denied any involvement. At the same time the story fails to make it anywhere at all on the Google News website. You can just about still find it on the yahoo news website but the story there somehow manages to work the Israelis into the very first sentence by stating:
"By threatening to ignite a Palestinian civil war, the killing of three children on Monday has jeopardized Israeli Prime Minister Ehud Olmert's efforts to restart long-stalled peace talks"
so that uninformed readers would be led to believe that it must have been to do with the Israelis.
In this particular story you cannot blame Hamas for covering up and/or smokescreening what happened. The decisions here are all down to the western media editors, who are so ingrained in their hatred of Israel and sympathy to the Palestinians that they simply have to minimise every Palestinian atrocity while maximising any perceived wrong done by Israel. Put simply, if Palestinian children are deliberately massacred by other Palestinians (even when it is by the elected Government) then that is not of interest. But if the children were accidently killed by Israelis then all other news stops for 48 hours.