However, I cannot get past this point. Non-violence may prompt violence, even though stopping the use of machinery was the primary goal.
And when we talk about using violence to persuade, we are now talking about terrorism, as you essentially point out, using fear for political control.
But let's make one distinction:
Sabotage is the use of violence against inanimate objects.
Terrorism is the use of violence against humans and other living beings.
Back in the day, the word "Eco-terrorism" was used by the right to describe what were actually "Eco-saboteurs". Burning an empty building on a ski resort, or disabling a ski lift, or pouring sand into an earth movers radiator, oil pan etc, all acts of sabotage.
There are those that argue as well, that violent saboteurs actually help environmentalism as a whole, because when one sees such physical destruction of eco-saboteurs, it makes the Sierra Club look completely moderate, if not conservative along a continuum (which they have always been in reality), and more likely to gain favor among the right, or anti-environmentalists when they compare to the "extremism" of the eco-sabatuers.
Or the way in which MLK could appear much more moderate to the right, not at all radical, when one compares to Malcolm X.
But who knows.