I find it interesting that this episode was the one and apparently only rerun this season.
I also find myself wondering about something else here - parallels between the island and the whole biblical 'Garden of Eden' episode.
Purportedly, the Garden of Eden had a couple of trees growing in it that had miraculous powers (Tree of Life, Tree of Knowledge of Good and Evil). The island has demonstrated healing abilities that rank as miraculous or dang close to it.
After Adam and Eve were evicted, God put a angel with a sword there to guard it. Now...at that point in the bible, all of humanity was 'tainted by sin'. The man in black regards all humanity in much the same way - hopelessly corrupted, and probably warrenting destruction. The mindset here would seem to mesh with that of the angel God put in the garden: humans could not go there because they were tainted/corrupted. Note that it is always Jacob - at least until the Dharma crew showed up - who brought people to the island, and the man in black appears to have killed most of them.
