There's a lot of truth to that.
For many of them, they're simply at war with us. And killing people is what you do in a war.
But Westerners somehow are convinced that the ONLY objective of terrorists is that we get mad at somebody and as long as we aren't mad at anybody, we're actually "winning" the war which of course also doesn't exist...
Of course, that's absurd in many ways, you would never apply that logic to any other problem.
Typically, as a rational person, you're trying to solve a problem. But in the context or religiously motivated terrorism, trying to solve something apparently means they've won because they "influenced" us. And we win by basically doing nothing because that will show them. As I've said, you would not apply that logic anywhere else.
If somebody repeatedly breaks into you and your neighbors' houses, you'd never say that the burglars "won" if you install cameras or a more secure door because that somehow proves that they've influenced your life.
Very difficult situation.