How in the world is it a music video? It's a documentary.
They consider feature length stuff as long form music videos. Concert videos and documentaries generally are nominated in this category. I think ZooTV Live From Sydney won or was nominated in 1994.
I understand concert videos. But documentaries are not musical. How do documentaries demonstrate musical talent? It's not even performance art.
This is from a category description guide. Which I found via Wikipedia. Maybe it's outdated :http://www2.grammy.com/PDFs/Recording_Academy/52guide.pdf
Long Form Music Video Videos Only
Award to the artist and to the video director/video producer.
• Music videos, released for sale to the public for the first time during the awards eligibility year.
• Music video programs that made a first appearance on broadcast or cable television during the awards eligibility year and which are synchronous or approximately synchronous to a recording commercially released during the awards eligibility year.
• Various artist videos, such as tribute or live performances. (Award would go to director/producer only.)
• Documentaries of musicians if music is a substantive part of the video.
• Music videos under 20 minutes in length.
• Non-musical programs.
• Compilation of short form or sampler video packages by various artists.
• Theatrical motion pictures which are or have been in general release.
• Any long form videos or promotional clips which were eligible in a previous eligibility year or compilations of such.
I think the key question here, is music a substantive part of From the Sky Down? I would say no.