If Ann Coulter thinks that every terrorist has been a Muslim, the women is an idiot.
How long has terrorism existed?. Answer: a century, give or take. How many terrorists have been Muslim?. Answer: some.
There have been thousands of terrorists, dozens of groups, thousands killed and maimed, all by terrorists whose ideology is not Muslim. In many cases not even religious.
So how can anyone with ANY knowledge of terrorism, of history, of the modern world, say that most terrorists have been Muslim?.
This issue is hardly worth a lot of my time so I’ll end my part of this exchange with the observation that Ann Coulter was quite obviously not commenting on terrorism throughout human history, as you referenced, but terrorism in the past 10 or 15 years, which has been primarily generated by Muslim jihadists. If you can’t grasp that obvious fact, then you have no business calling anyone else an idiot.