I saw that also, and I asked one of the CMs if you really needed to line up that early if you had a Fast Pass, and she said no. That many of the people sitting there were not even in line - they just wanted to sit and there are not a lot of places to sit in Asia. She did say be there at least 15 minutes early.
And FWIW, you can scan in at any point once they open the gate. My FP+ said 6:35, but when I walked there at 6:15 they were letting people in. I asked that CM and he said that once they open, it reads all Fast Passes for that showing regardless of time.