It should be noted here that setting the following distance is a meatsack function. There's a control with a range 1-7 (from memory) which sets the time interval to follow behind.
This one looks to me like it's set to closest follow distance, which is pretty damn stupid. I always use any intelligent cruise control on maximum separation, personally.
Now, if you want to debate why the meatsack is able to set the following distance, I'm right with you - prime evidence that the people designing these system don't quite grok safe driving, to me.
But then, the group mostly involved in cutting-edge programming are also the same group most over-represented in collision statistics - young males. Go figure...