Thanks to Christiaan for sending out the initial news and thanks to Andrew for this most recent follow-up.
For better or worse the backstory provides important context for this crime. I would feel safe betting on this as not having anything to do with whether the person was on a bicycle or not.
Key facts for those of you unable to read the story:
1) Victim and assailant knew one another and had interacted minutes before the assault
2) Victim and assailant were engaged in self-reported illegal activity (drug dealing) prior to assault that strongly suggests alternative motivations for the crime (alternatives to aggression towards cyclists in general)
-Drew