That guy was going WAY to fast for the circumstances.
Mass ride, pedestrians, etc.
If he had been still fast, but reasonable, he could have avoided that other bike easily.
As to the guy who got nailed, it's called an indicator, would have given that second's worth of head's up.
We ride a lot marshalling cyclists, and i often do high speeds next to those monkeys (cyclists), and have had a few close calls (favourite was a cyclist who blindly crossed 3 lanes of shut down highway, into the fast lane us marshalls and emergency crew were using, took him about 3 or 4 seconds to cross 3 lanes, i was doing about 140km/h when i saw him on collision course for me).
This guy was just too fast for the road and traffic. And his own skills apparently.