You can't hit the QB high, i.e. in the head or neck area. You can't hit them on or below the knees. You have to time your hit perfectly or it will be late. And yet, no stat probably does more for a defender's payday than sacks/forced fumbles.
The flag football comment should not be taken as an exaggeration. Seriously. They should just go ahead and put small flags on either side of a QB's waist, and consider him sacked/tackled once the defender has one in their possession.
The current system is ludicrous.
I sometimes feel that between the media and some fans, The NFL will turn into flag football fill with a bunch of boring behind people paying it.. So sick of the pious attitudes.