Generally speaking humans are a pretty nasty lot. Look at how many wars and how much blood was spilt that way in the 20th Century alone. We are barely into the 21st Century and still we are developing better ways of killing one another. If we didn't feel somewhat protective toward our loved ones there wouldn't be a human race on this planet today.
The reason why the Cold War remained Cold was that the Russians loved their children and wives or husbands so much they didn't want them to die in some atomic explosion. The Americans of the day felt the same way. So yes. Love does protect. Will it always protect? Well, only the future can decide that one.