If one guy ignores the law it’s his fault. If everybody ignores the law then it’s the law’s fault. If everyone ignores a speed limit sign then the sign is not working. Simple as that!

You should care if some asshole road rages at you and inflicts violence on you, the way a driver did to my dad when he was following a speed limit on a road people routinely speed on (which has seen extensive modifications over many years to try to combat speeding). It’s terrifying and extremely dangerous.