What I don't understand is how a victim is supposed to know the intentions of a criminal before it is too late. What the Bad Guy may do during a crime changes with opportunity. That reality is the rationale for the Castle Doctrine, and valid in my opinion.
Exactly.
The law in most states runs contrary to long established precepts of common law that date back to the Middle Ages and before.
Before it was labeled "castle doctrine" precepts of self defense were embodied in various doctrines known as "provocative acts" or "fighting words" among others.
Your grandfather and certainly your great grandfather were familar with the concepts in one form or other.
When a burglar or mugger initiate a sequence of events, they, the burglar or mugger are responsible for all that follows up to and including their own death or the death of others.
The trouble starts when "some people" do not want "other people" to be able to avail themselves of the benefits of these precepts.
Thus when a Jim Crowe era lynch mob chased a victim down for extra judicial proceedings the members of the mob did not want to run
the risk of a charge of "provocative acts" when one of their members was shot by the intended victim. So they passed possession laws or prohibitions against use etc. intended to apply to certain people.
Hence, the racist or class related roots of most modern gun control. The mob members had no thought the laws they initiated would one day apply to their children or grandchildren.
Jane Fonda and her husband of the time Tom Hayden both owned pistols because they honestly believed gun control law only applied to "the little people'.