Because the US is not a no fly zone.
There's no prohibition against flying that particular drone model in the country.
DJI just isn't releasing it yet because of
The problem sorting out issues around what to charge for the drone because of...
The long, slow download is because he has a bunch of the all-I video files that are up to 9GB.
You can just select the .dng files to see the stills and leave the .mp4 video files.
Is that a problem when you are shooting a full frame SLR?
That's a question for the technical people at DJI, but my guess is there's a good reason for it.