I agree with Dr Alf that this is the very least that has to be done.
Jihadis who call for Caliphates to rule over other countries and ultimately the world are traitors and seditionists and the penalty for that should be severe not just a slap on the wrist.
Similarly, calling for the death of unbelievers, kuffirs, apostates by beheading, the bullet, being buried alive and being crucified is incitement to murder, especially if they suggest that they are going to travel home and do the same things there.
The UK has a former supermarket guard who used to be employed by Morrisons boasting about beheading people in Syria and saying openly that he wants to do the same here.
Others no doubt want to wreak havoc in their own country.
Provided we keep these people bottled up in Syria and Iraq, preferably in a desert area without much population, we can probably neutralize them remotely, avoiding the need to risk the lives of our troops. Another option is to deploy mercenaries.