--Many today troubled by violence of OT. Several factors to note:
(i) Divine punishment on sin. Canaanite religion seen by biblical writers as thoroughly debased and contaminating.
(ii) God equally hard on Israel, subjecting apostate cities to ban. Israel eventually exiled because of sin.
(iii) OT had no developed concept of afterlife, so divine punishment or reward was applied in this life, not the next. In the NT, God's punishment of the impenitent is equally severe, if less immediately obvious.