Terrorism or not is not even the problem, and whether it stems from a 'misguided' Islam or from Islam is not the question.
Even 'right guided' Islam wants an Islamic Emirate or Caliphate and Sharia as the fundaments of their state, which is 100 % incompatible with Western ideas of human rights, rule of law and democracy.
This, obviously, cannot be allowed in Western states even if it does not come with terrorism but by peaceful means.

In short, it's a rhetorical trick, that implies everything is okay with Islam in Europe as long as it is not associated with 'terrorism'.