And what is wrong with what they advertise?
In most airports I've been through, priority queues are most of the time quicker than non-priority queues, of course you can't avoid it completely, it only takes one family that requires some extra documentation in the queue to clog it for some time, or said family travelling in J for the first time in their life and have no clue about what they need to take out of their bag for security etc.
If at a specific airport there is an issue with the priority queue being constantly slower than the non-priority one, then this should be addresses with the airport/immigration authorities, but I don't see why it makes the advertisement a false one.