The Bible is one of the oldest collections of writing you will ever read. The stories in it were passed orally for centuries before being committed to parchment. It was Star Wars for pre-medieval times.
The Bible condemns murder, but sanctions violence in the name of the greater good. The problem is not God, it’s us. Humans, once they start doing evil things, if they’re not stopped and punished, they’ll keep doing them. Then they’ll start subverting other people into doing them too.
The first murder performed in the Bible was that of Abel by Cain. God punished Cain, but also had mercy on him by protecting him. It’s all well and good when God is available to mete out justice as needed, but when you start having large organizations of people, civility and order break down in weird ways. God needs to mete out justice on the scale of entire populations, the first of which was when He found it necessary to drown all of humanity in a giant flood with the sole exception of the righteous Noah and his family.
The Bible gives an example of God refusing to allow someone to get stoned, when Jesus stayed the execution of an adulterer from ugly and duplicitous accusers. Even though she was guilty, Jesus looked at the wickedness of the witnesses, witnesses which were by law required for a guilty verdict, and demanded they live up to the moral uprightness that they were claiming.
I suppose you could ask God to be everywhere at once, but at some point that just turns into asking God to solve all your problems for you. Humans are going to kill each other no matter what, so you might as well give them some divinely-acceptable outlets in which they can do that.
So, to answer your question, it’s because it’s people that suck, not God. God can’t get personally involved in everyone’s lives, not without making His plan moot anyway, so He gives people examples to live by. These examples are documented in the Bible.