I see precious little difference between the person who swears off medical treatment for their child who's suffering from an illness, and the person who swears off lethal defense of their child who is being attacked by a violent criminal.
I'm not saying that distinctions cannot be made between one and the other. I'm saying that, even with those distinctions in mind, I consider them to share so much in common that they either stand together or fall together. If it's reprehensible to fall back to prayer alone for cancer, it's reprehensible to fall back to prayer alone against a violent intruder.
Christians are called to do good in the world. We are called to forgive beyond the norm. We are not called to be suicidal idiots or complete pacifists, which are many times the same thing. The person who allows themselves and their families to be slaughtered, without justice or provocation, is not a noble imitator of Christ. They are a cartoon mockery of Christ. They wouldn't help the good Samaritan - they would lay down and die with him while yelling 'I'm helping!'