I've seen some people on the left, at least, who are pretty explicit about their denunciation of reason. These types will say things like:
* "rational argument doesn't change minds, only mockery does" (one wonders how they think that they came to believe what they believe!)
* "don't argue with racists"
* "the Democrat Party is too nice and reasonable. We need to fight dirty like the Republicans. Our focus on truth hasn't gotten us anywhere."