It was reasonable for people to regard the Earth as flat so long as there was no good evidence to the contrary, but one would not call it a matter of consensus

It was reasonable for people to regard the Earth as flat so long as there was no good evidence to the contrary, but one would not call it a matter of consensus today just because some people might be unaware of the evidence, fail to understand it, ignore it, or choose to deny it without attempting to refute it. Alternatively, one were to insist that this means that it is still a matter of consensus, then that would amount to defining 'consensus' in a way that is useless for this discussion. The bleaker truth about evidence, facts and politics is that people are arguing for a preferred outcome, and will, to a greater or lesser extent, simply turn to rationalization (sometimes of a quite irrational type) if the evidence does not support their preferred outcome.