WP - Optional Write Protect. When active low, WP prevents any changes to the present contents
That is simply bad wording in my opinion. As already stated, the phrase "active low" means that the pin does whatever (i.e., it's active) when the input is low. So there's no state called "active low." There are only high and low states, and the pin's function is either activated by being high or low. To put it one more way: It can't be active low, it can only be activated when low.