Actually, it's a Christian tradition (!!!). Halloween was originally called All Hallow's Eve; just before the Feast of All Saints is the last time evil spirits can freely roam the Earth before being pushed back to Hell by the combined power of all saints.
Watch Disney's Fantasia again: right after Mussorgsky's Night on Bald Mountain, where the Devil minion's revelry is cut short at the first stroke of midnight by a church bell, comes Schubert's Ave Maria...
No, I don't expect Fundies to understand this.
Besides, horrible monsters from the pits of Hell have also benefited from our civilizing influence: at first, they forcefully snatched our souls, but now, they kindly ask for candy.