I would argue the conclusion to that isn't that they don't have a valid point, but that the people cannot be sufficiently motivated, or that they are unsure how to protest effectively, or that they are unaware that disrupting often leaves people feeling disrupted, that feeling disrupted is not a positive feeling, and that associating Negativity with a movement too many times can really hurt it in the long run. Just look at the cultures idea of PETA in the USA.
I argue that PETA succeeded to bring into the official discussion other, more moderate organizations, thus effectively moving "the cause" forward at the expense of their own organization. Probably that was not their goal, but from a 10.000 feet it looks like achieving that. I think the same goes with the "eco terrorists", they may get slaughtered in the process but ecology gets on everybody's tongues. Again not sure they are planning it like this or it's just a side effect.
