Another view is that it was actually the spirit of Yahshua in Noah that did the preaching to living people prior to the flood. This would presuppose a preexistent Savior , a view which I reject. Consider a third view which appears to be more Scriptural. So verse 19 is referring to an event that took place after his birth to Miriam. Men are not spirits, men have spirits.
Men also have flesh and blood bodies.
Therefore, this cannot refer to living people in Noah's day, nor can it refer to disembodied spirits of people burning in hell since no one is burning yet as we saw earlier. It is to angels that verse 19 is referring. Even as Sodom and Gomorrha, and the cities about them in like manner, giving themselves over to fornication, and going after strange flesh, are set forth for an example, suffering the vengeance of eternal fire. Yahweh had set the boundaries of their habitation and they chose to disobey. As a result, they are imprisoned until the time of their judgment arrives.