The rabbis suggest that the conflict in Genesis 13:7 is a story about the wickedness of Lot’s herdsmen who hoped to gain in Abram’s blessing. With no natural heirs of his own, Abram’s possessions might go to his nephew; the greed of his herdsmen caused them to harass Abram’s herdsmen.
Some suggest that Abram's herdsmen were the instigators, believing themselves entitled to Abram's blessing, to the exclusion of Lot's family and herdsmen.
Perhaps they're all to blame.
And there was strife between the herdsmen of Abram’s livestock and the herdsmen of Lot’s livestock. Now the Canaanites and the Perizzites were living in the land at that time.
Genesis 13:7 (NASB)
But this is also a story about “strife.” In Hebrew, this is “reeb,” and means “contention,” or “debate.” It’s often used to describe the kind of dispute that requires an impartial judge to step in and give wisdom.
Sometimes there is no “right” answer. There is only God’s wisdom.