I think this is purposely confusing two different arguments.
Nobody can deny that oil use is becoming less and less attractive and that is a good thing for everyone.
But if it is "on the way out", what's the need for blocking the pipeline? The need is that actually there are still significant usages of oil remaining even though it's "on the way out".
So those significant remaining usages actually DO add validity to the argument that blocking the pipeline will cause additional demand for oil trains/tankers. Otherwise there wouldn't be a need to take any action at all.