There is a difference between saying “I want to move into a place which is more free in the aspects of liberty that are directly relevant to me and mine” and saying “X is not important.”
As a matter of fact, even if we omit the moral issues involved with this given problem of drug prohibition, here's something to consider: No index is scientific and none may encompass all liberties (which is why I dislike indexes in the first place). There are dozens of issues on which legislators may have to decide tomorrow – say, regulations involving ATVs, or toys, or whatever. I would like to have a measure predicting at least vaguely how the locals would react to a completely new issue. A state with a higher freedom rating would , I suppose, be more liberal in deciding a new issue, even if the rating was achieved by ranking better in stuff that doesn't directly affect me. Does this make some form of sense?
[For the record: I view homeschooling as extremely important. Not only do I think it should be legal ,but I think that the world would be better if more people did it.]