It's possible, but if, say, pro-pinapple speech and reesearch is effectively and heavily suppressed, then even if the lone nutters who are pro-pinapple (and you'd have to be a bit of a nutter to be pro-pinapple in an anti-pinapple world, both due to lack of exposure to anti-pinapple resources and for social reasons) speak up they are probably not going to make a good case, not having had the opportunity to explore the idea with a large number of different people helping them figure out the arguments and doing the experiments.