I've been down the track hundreds of times, and I have made that same mistake myself.
Once you see the evidence, I think you'll agree....
First, in this picture, you can cleary see the white line, and it definetly looks like your rear tire is staged on it.
The next shot, shows the white line again, and zooms out a bit more. You are fully staged at this point.
You can also see the front end of your car CLEARLY many feet BEYOND and IN FRONT of the white line.
However, in the lane NEXT to you, there is CLEARLY no car visible. So, we can say that either the next lane is EMPTY, or the car staged is a moron and staged well BEHIND the point that you staged at.
This next shot shows the tree coming down, and is only a few frames before launch. Still, no car present in the other lane.
The last and final shot shows the car in the lane next to you actually passing you. This person had a much better reaction time then you and out 60' you by a clear and visible margin. However, if we were to take a look at their slip, I'll bet their reaction time advantage, plus their clear short time advantage does not stack up to your 60', showing that you had an advantage at the tree caused by your severe deep staging.
At this point, the car in the previous lane is already in motion, and has been for a short period of time. However, their front end is JUST NOW passing the front line. While your car, which has also JUST started to move is still well beyond the white line.
Make of this evidence as you will, however, I certainly wouldnt mind hearing an account from the driver in the WRX, or seeing another video angle of this particular pass.