No, there are actual terrorists and have been for ages, though they used to be called anarchists. Attacks on targets by Northern Irish terrorists were a Real Thing. It's the scale and scope of the response that are disproportionate, not to mention the moral vacuity of same.

Calling them anarchists makes them less invented? Calling them Northern Irish terrorists makes them less invented? No.

It works like this. You are a rich fucker who wants to mug a country. To do that you need an army. So first you locate some traumatized people. Feed them money and motivational ideology. Point them at your target. Profit.

Voila, you have invented a band of terrorists.