What is rational?

Someone might not have read their Wittgenstein, let alone their Bakhtin. At Overcoming Bias, we find:

[People give] views on risks of nanotechnology even when [...they] know that they do not know much about the subject and these views become strengthened along ideological lines by more facts. Facts do not matter as much as values: people appear to make a quick gut feeling decision (probably by looking at the word "technology"), which is then shaped by their ideological outlook.

[...]

This does not bode well for public deliberations on new technologies (or political decisions on them), since it seems to suggest that the only thing that will be achieved in the deliberations is a fuller understanding of how to express already decided cultural/ideological identities in regards to the technology. It does suggest that storytelling around technologies, in particular stories about how they will fit various social projects, will have much more impact than commonly believed. Not very good for a rational discussion or decision-making, unless we can find ways of removing the cultural/ideological assumptions of participants, which is probably pretty hard work in deliberations and impossible in public decision making.

Does the author believe that the 'rational' decision is something other than the average community decision? What does 'rational' mean, when we are talking about language, if it isn't 'what most people agree follows'? Is there a manual on correct deductions in English? Is the only person without 'cultural/ideological assumptions' the author? Or is the assumption that a certain mode of discourse is the only rational one itself just possibly a cultural/ideological assumption?