If the law had defined a death sentence for a home invasion, then you might say that. It certainly doesn't. The people who wrote it don't value material possessions over human life.
The Castle law simply gives you more rights in the questionable home invasion situation, but it's really easy to abuse it and this makes it basically a license to kill people on your own property.
People in the US tend to abuse laws from what I've seen. You have an amendment that says that you have the right to carry firearms, and now everyone and their grandmother is carrying a firearm. It's not mandatory, it's optional.