Game of Thrones

Through UVerse I am subscribed to HBO.  I can only find Season 1 Episode 1 of Game of Thrones through on demand.  It does not show all episodes or season.  When I log into UVerse.com, all the seasons and episodes are available to stream online.

Why does UVerse allow you to stream any Game of Thrones episode online but does NOT allow it for the TV.  It does not make sense.

Thank you.