I think it's more a legal issue so they can cover their asses for their advertising insinuations that OSX is immune to viruses.

Now people can't blame/sue Apple when the first big Mac virus does hit.

And if he is installing to a low CPU power machine with no DVD drive and no/slow net access?

This is the only reason people are even interested in the CD installer in the first place.

Just because Linux installers can't handle partitioning in the way you'd like automagically (what the hell does this have to do with the OP's problem?), doesn't mean BSD shouldn't have to fix their CD installer.

Actually, that's normal for Star Trek now.