Just like in the fiat case, the attacker of a currency peg has enormous upside if the attack succeeds and essentially zero risk if it fails: the peg can only go

Just like in the fiat case, the attacker of a currency peg has enormous upside if the attack succeeds and essentially zero risk if it fails: the peg can only go down, not up. So shorters pile on to the diseased currency like lions biting a dying antelope, it's not a question of IF it will go down, it's a question of WHEN and what is the most profitable and likely to fail peg you can pit your capital against. These days, there's a whole herd of them.