The prevailing opinion isn't always the one most written or voted. There is an activation cost to spreading your opinion, and writing is often the act of last resort (ie, no definitively positive action is available).

In the previous situation all that agreed with the TPP need do nothing, as it looked sure to pass, so the argument was not worth having for them. The anti-TPP had very few positive actions available to them so it largely fell to writing.

Now the anti-TPP position has prevailed those against the TPP see little reason to debate it, yet those who were for it are left with nothing but writing.