What's so scary about any plan to establish the caliphate or Islamic Government?

I'm reading this news over here about a radical Islamic group in a western country that wishes to establish a caliphate or Islamic government.

The court in Antwerp sentenced the Sharia4Belgium group's "charismatic leader," Fouad Belkacem, to 12 years' imprisonment and gave dozens of other members lower sentences. Belkacem, who was led into court in handcuffs by police in body armor, smiled as he listened to the judgment. Other senior leaders of the group were sentenced to 15 years because judges said that, unlike Belkacem, they were actively involved in terrorism in Syria. The verdicts came in one of Belgium's biggest ever terror trials — 46 Muslims were originally indicted, though only a handful appeared in court. Others are believed to be fighting with Sunni armed groups in Syria or to have died in its civil war.

Muslims and non-Muslims have every right to fear loud-mouthed idiots who think they can implement a Utopian styled-Islamic government forcefully anywhere on planet Earth. This short sentence below (from the news article) highlights everything that is wrong with a faith based government, namely Islamic government, but it can also be easily extended to Christian, Hindus or other belief systems.

The written judgment said that in the "totalitarian" Islamic state Sharia4Belgium wanted, "there is no freedom, no human rights, no place for personal development, science or culture. Their state is based on violence and fear.

Reference
http://abcnews.go.com/International/wireStory/court-islamic-group-terror-organization-28882299