Why did God demolish the Edomites?

According to Ezekiel 25:12, it was "Because that Edom hath dealt against the house of Judah by taking vengeance, and hath greatly offended, and revenged himself upon them;" The Edomites are descendants of Esau, who was the brother of Jacob (Israelites), but joined forces with the attackers of Israel, blocking the Israelites from fleeing rather than helping them.