Question

why is war against terrorists difficult to fight?

Answer 1

Because they aren't walking around carrying signs that say "I want to bomb X country."

In depth, American's believe that Religion Y is accountable for producing the majority of terrorist, but we can't just assume all of people believing in Religion Y are terrorist.

Answer 2

Because the Terrorist organization doesn't have a Government.

Answer 3

So there's nothing that we can take out that would collapse the whole thing. It's like trying to cut the head off of a snake without a head.