The term "eco-terror" is nothing more than a politically-correct attempt to soften the crime. It's criminal activity: no more, no less. When you commit arson you've committed arson, you've committed a crime, and it should not matter in the least that you did it to:
make a protest for the "ecology"
knock down a rival gang
kill someone
cover up another crime
knock down a resister to your extortion racket
get your jollies
make a political protest
exact revenge
and so on.
IMHO, given the readiness with which the radical Islamist world would latch on to these people (if they had the intelligence -- but I'm not saying who the word "they" refers to :-), "eco-terror" could well be considered as, and maybe even indistinguishable from, treason.
(Caveat Lector: This is only an instant analysis after a looong day at work. There may be good reasons to make the distinction that I don't see at the time of posting.)