It seems like the situation you witnessed is quite interesting! Traffic violations, such as beating the red light, are serious offenses that can endanger the lives of both motorists and pedestrians. It's important for traffic enforcers to enforce the rules consistently to ensure the safety of everyone on the road.
In this particular case, it appears that the traffic enforcer chose to stop the motorcycle instead of the bus that also beat the red light. While it may seem unusual, traffic enforcers may have their reasons for prioritizing certain violations or vehicles based on the severity of the offense, the level of risk posed to others, or other factors.
It's also possible that the traffic enforcer may have had a better opportunity to apprehend the motorcycle due to its speed or proximity, whereas stopping the bus might have been more challenging at that moment. Regardless, it's important for traffic enforcers to be fair and consistent in enforcing traffic laws to maintain road safety for all.