Actually, it isn't surprising that 10.6 isn't available via internet recovery. That version only exists on DVD, at least AFIK. 10.7 is the earliest version that wasn't available on DVD.
Actually, Lion
was available on "DVD", but the DVD was a thumb drive.
As I said, though, "...Lion
is the earliest version of OS X...with IR capability" (although it doesn't seem like it would have been much of a big deal for Apple to throw Snowy onto the server).
