This point in particular is extremely easy to answer. God has given people, and angels, agency, or the ability to act for themselves. It is His greatest gift to his creation outside of salvation. He will not violate our agency even if it means that He is hurt by our choices. He loves all of his creation and is grieved when one agent chooses to harm another agent, but to take that choice away from the first in order to protect the second supernaturally is not something that God is willing to do, for the sake of the agency he granted to the first. I believe that every time someone gets hurt by someone else there has been a failure to listen to God on the part of at least two parties.
Firstly, the party doing the hurting. They have obviously not listened to God when he is screaming to them to not do what they are planning. Their heart is too hardened to hear Him.
Second, the person who is hurt has, in many cases, heard something in their spirit that says not to go that way, or not to leave yet, or some other thing that would have kept them out of harms way. That still small voice has spoken and they have chosen not to listen because they have their heart set on a course of action, or they have not heard at all because they have chosen to block out that voice.
Third, the party who heard God speak in their spirit to do something that would have helped the injured party, but they didn't understand why they needed to do that so they ignored it. I know for a fact that this happens. I have a friend who heard the Spirit saying that she needed to get off the highway in a bad part of town in the middle of the night. She did. She then had the feeling that she was to go into a convenience store and stand on her head, and then leave. She almost said that was too nuts and simply got back on the highway. She was prompted again and she decided that, even though she didn't understand, she would trust what the Spirit was saying. She went in, did the deed, and walked out laughing. The clerk stepped outside and asked her why she did that. Without hesitation she responded that she didn't know, other than that God had prompted her to. He started crying and told her in a nutshell that he told God that he was going to kill himself if someone didn't come into the store and do something crazy for no apparent reason. He became a Christian and I heard him personally tell that story (I've also heard it from her, but his telling made it less anecdotal because he had the emotion of what it did to him). I used to work at a convenience store in the worst parts of Kansas City overnight. I was almost robbed several times, and something happened every time that stopped it. I had a cop walk in at the same time that a dude was reaching into his waistband for a gun. I said something about being lucky he was in the neighborhood and he told me that it wasn't luck. God had prompted him to turn around and head back to the store. These people listened to what God was asking them to do and kept people from harm. I believe that most people, even Christians, ignore that still small voice and it causes someone harm that would have been unharmed had the person listened.
Long way around to the point that agency is something that God will not violate. Even Satan's.
