I assume that そう here is the そう used for not direct quoting.
This を is merely a direct object marker, indicating the object of the verb 呼ぶ.
AをBと呼ぶ means "to call A B".
(They) call people who don't drive at all paper drivers.
In this case, the adverbial phrase ペーパードライバーと is replaced by そう, which is like "so", "that way" or "like that" in English.
(They) call people who don't drive at all like that.