The mosque is not a place of worship, only a small section of it is devoted to worship. A mosque serves many purposes including meeting place, adjudication, etc etc etc.
The following quote from Dr Peter Hammond is instructive:
Dr. Peter Hammond ( doctorate in Theology), "Islamic Slavery and Terrorism: The Historical Roots and Contemporary Threat". "Islam is not a religion, nor is it a cult. It is a complete 100% system of life. Islam has religious, legal, political, economic, social, and military components. The religious component is a cover for all the other components. Islamization begins when there are sufficient Muslims in a country to agitate for their 'religious' privileges. When PC and tolerant societies agreeto Muslim demands for their religious privileges, the other components start to creep in as well.