I don't think there is any 'holiness' or 'sanctity' in any islamic building or belief... But what makes it all the more obvious is the fact that muslims kill other muslims in mosques all the time. It is also well known that the muslims will often hide weapons in mosques... Obviously they can't believe there is anything 'sacred' about a mosque. Thus I don't know why they cry when the IDF bombs them. Mosques are and always will be valid targets.
Here is a story about the President of Yemen who was nearly killed in a bomb attack on the mosque he was praying in...
http://www.israelnationalnews.com/News/News.aspx/145181Yemen's Saleh Not Returning Soon
by Gavriel Queenann
Western diplomats say Yemeni President Ali Abdullah Saleh is not likely to return to Yemen soon, Reuters reported Thursday.
"We believe he was seriously injured ... He is not coming in the coming days, he is not coming soon," the diplomat told Reuters.
Saleh is currently in Saudi Arabia where he is being treated for injuries sustained when a bomb exploded in the mosque of the presidential palace in the Yemeni capital, Sana'a on June 3.Western diplomats also added that the explosion targeting the mosque of the presidential complex on June 3rd, was caused by many bombs planted in the mosque.Yemeni security officials confirmed that five explosives inside the mosque and a sixth one outside it didn’t explode..
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Mosques are just a convenient place to expunge the world of filthy terrorists...