What did Edom do on the day strangers carried off Jacob's wealth?

Answer: Stood aloof

Edom stood aloof while foreigners entered Jerusalem's gates and cast lots for it, and so was "just like one of them."

“On the day you stood aloof while strangers carried off his wealth and foreigners entered his gate and cast lots for Jerusalem, you were just like one of them.”— Obadiah 1:11 (BSB)