Idk why you guys keep harping on the signaling part. Even if car driver did signal, it doesn't give him the right to proceed without ensuring it was safe to do so.

Yup, some only signal after almost completing the lane change in a dangerous way. Macam trying to mitigate or something like that.

You just described defensive driving/riding, which many bikers don't practise. In Penang, bikers seldom honk in situations that they should, macam will become pondan if they honk.

Any stationary car with driver still inside (signal light on, brake lights on, etc) is a potential hazard - door open suddenly (seen a few times), car suddenly moves out/turn out/u turn...

I wasn't specifically referring to this case.

Example:
1. a car parked head in is reversing out. Moto is approaching the car. Moto will try to avoid the car instead of honking. Car happily reverses out and bam...

2. A stationary car at roadside signals right. Moto suspects it's moving but doesn't honk, instead it tries to avoid it. Car U turns and bam...