It’s legal to drive with the speed of traffic for your own safety

This is pure misinformation. It is illegal to exceed the speed limit. Simple as that. It is illegal to go 66 in a 65 zone. It is illegal to go 75 in a 70 zone. Anyone who says otherwise is spouting pure fiction.

Now, what you might be referencing is police choosing not to enforce the speed limit on people speeding by a very small margin. That is a conscious choice by police officers, and they can and will find any moving violations to pull someone over if they want to.

Though that sort of makes sense for traffic moving smoothly and consistently, I thought speed limiters on large/heavy vehicles was mostly due to the braking time/distance rather them fitting amongst speeds of other traffic?