1)
Why did they not kill anyone? David killed many of them!
1.
Radak (1): Hashem caused this; He guards his loved ones.
2.
Radak: There were no men there to fight. David and his men left, leaving only women and children.
3.
Malbim: It was Hashgachah that they took the people captive, so David would be obligate to save them, and exempt from helping Yisrael against Pelishtim.
