> This reasoning makes very little sense to me.

The reasoning doesn't make sense because it is applied retroactively. The parent poster doesn't want to take responsibility for their unsafe driving practice and tries to place the blame on the other driver.

Cars suddenly stopping in front of you isn't some unpredictable rare event. You are told this as part of the licensing procedure, and this is the reason minimum safety distance exists. The solution is obvious and known to any licensed driver. As such, it is unreasonable and unacceptable, to not follow the minimum safety distance.

Thats not my point. You should, and I do, always leave enough space to stop, but not everyone does.

Being a safe driver is being aware that other people, including the people behind you, may not be leaving enough space. Suddenly stopping for a rabbit, from a speed of 50mph, is f-ing stupid and massively increasing the risk of a serious accident on the road.

Using a Level 2 automation that can randomly stop for no reason is not safe driving, you are increasing the chances that someone who is too close drives into the back of you.

Just because someone else is driving unsafely doesn't absolve you of the responsibility of being aware of that and not driving safely yourself.

You should be able to stop at any time for any reason and not worry about the car behind crashing in to you. They should leave enough space. A rabbit is a very good reason. Maybe it's not a rabbit, maybe it's a rabbit-shaped rock that would cause serious damage to your vehicle, causing you to leave the road and die.