I'm surprised at the mis-judgement by the chap in the OP's video.
As a biker myself, I'd suggest that one of the things you learn quickly on a motorbike is how to judge speed very well!
TBH, he could have got out in front of you easily, he just should have done it a bit more sharpish - lean into the turn and grab a handful of throttle - he would have whipped round and been halfway down the road by the time you'd got to the junction. Instead, he potters out like an old granny!
EDIT: Also, looking at the vid again, his road positioning was completely wrong. He was on the left side of the lane, turning right. And he didn't do a lifesaver either. Fool!