It is possible that you don't know which port you're sailing to because you have ruled out some possible destinations, but there is still more than one possible destination remaining. If so, it's certainly possible that a wind could push you away from all the good destinations and towards the bad destinations. (It is also possible that a wind could push you towards one of the destinations on the fringe, which pushes you farther from your destination based on a weighted average of distances to the possible destinations, even though it is possible that the wind is helping you.)

(Consider how the metaphor works with sailing=search for truth, port=ultimate truth, and bad wind=irrationality. It becomes a way to justify irrationality.)

The difference between "no knowledge about your destination whatsoever" and "not knowing your destination" is the difference between "I don't care where I'm going" and "I don't much care where I'm going" in the Cheshire Cat's version.

Even if you don't know which port you're going to, a wind that blows you to some port is more favorable than a wind that blows you out towards the middle of the ocean.