Lack of political will
The threat is not important in itself. The supporters of terrorism are too few and too marginalized to be considered a serious public security threat.
However, state inertia and political support from an obscure center have given them the asymmetrical power that allows them not just to disrupt city life, but also – and most importantly – to threaten judicial officials.
The problem, of course, is not a matter of police presence and this is why it can be quickly resolved once there is a basic level of political will to deal with the issue.