Well, I deliberately left out the source because I didn't think it would play well in this Peoria of thought -- it's from his book of essays Farewell to Reason. Link to gbooks with some context.

We've had rationality quotes before from C.S. Lewis, G.K. Chesterson, and Jack Chick among others. I don't think people are going to complain because of generic context issues even if Feyerabend did say some pretty silly stuff.