the other reason tons of people still advise lots of reps for abs is that way too many people still cling to the old wives tale that you can spot reduce your ab fat (or any other area) by "burning"it off with lots of reps.
i have tried to correct several people in my family about this notion and they totally and absolutely ignore anything i've said about it.
all those silly infomercials hawking those flimsy plastic jiggers for "getting washboard abs in minutes a day" dont help either.