These laws, castle doctrine, are not anywhere near that crazy. They’re the same idea as self defense… however, normally you have a “duty to retreat”, what castle doctrine says is if you’re in your own home you no longer have that obligation.

You still have to meet the bar for self defense, i.e., they need to be a threat… someone walking in your yard or knocking on your door that’s not brandishing a weapon is not going to meet that bar.

Edit: Wikipedia disagrees with me … though I’m not sure if that’s a factual disagreement or an editorial disagreement.

Justifiable homicide[2] in self-defense which happens to occur inside one’s home is distinct, as a matter of law, from castle doctrine because the mere occurrence of trespassing—and occasionally a subjective requirement of fear—is sufficient to invoke the castle doctrine. The burden of proof of fact is much less challenging than that of justifying homicide in self-defense. It would be a misconception of law to infer that because a state has a justifiable homicide in self-defense provision pertaining to one’s domicile, it has a castle doctrine protecting the estate and exonerating any duty whatsoever to retreat therefrom.

There’s a lack of citation here which honestly should probably be raised on the wiki. The cited source does not support that text (I’ve added the appropriate citation requests on the wikipedia side – if anyone can prove these claims, we should contribute the reference there as well).