eg lets say we load a bunch of shrapnel into a tree so it maims or permanenly injures whoever the next logger is...tha is basically the same thing as lobbing hand grenades into the public square. the attacks are meant to target random people, caught unawares, in a way that conveys a persistant threat of continued, scalable future action.
Now lets take some other shady randome violence like the KGB assinating a civilian in London with radioactive isotopes in his tea. Is that terrorism? No, its a specific threat carried out in a limited capacity against a designated target. It might be criminal or a war crime or wahatever bad thing describes it, but its not "anti civilian warfare", in the same way that not all war casualties are "war crimes" in the normal usage.
> THE senior British official was unequivocal. The murder of the former KGB man Alexander Litvinenko was "undeniably state-sponsored terrorism on Moscow's part. That is the view at the highest levels of the British government".
http://www.thesundaytimes.co.uk/sto/news/world_news/article6...
You might think that some forms of terrorism are worse than others, but that doesn't mean that those are the only forms of terrorism.
This is of course a slightly academic use of the word. Many people have a hard time seeing even traditional domestic terrorism (like the unabomber) as terrorism.