a cyclist should be treated the same as any other vehicle on the road. they might need to swerve to avoid an obstacle while the car is overtaking, just as a car may need to swerve while another car is overtaking. when a safety margin is possible, as it was here, it costs nothing to apply one.
I don't know where you live that you have that much space. My personal rule is don't swerve. If you don't have time to signal that you are going to move, or look to make sure other traffic is not in the way, then either brake hard or continue straight (with the obvious exception if not swerving causes you to hit another person).
There are just too many roads where you can't swerve without causing a head on collision. If you make it a reflex to swerve, then you will also do it when there is no space for other traffic to avoid you.
