Bullshit. With covid if I wear a mask and you don't there's still been a significant decrease in risk of transference and both of us are safer. With not going the speed of traffic, if I strictly follow the speed limit and you don't there exists a differential that increases our risk equally.

Speed limits are one of very few, if not the only, legal limits that is set by observation of actual human behavior. Look into how the 85th percentile rule is used (in the US). If a speed limit is set too high or too low compared to nominal human behavior the state creates a difference in perceived safe speed and strict adherents. It is that difference that causes problems.

There are parts of Atlanta where the speed limit is dynamically set (sometimes down to 40mph) and the flow of traffic is maintained at 20-30 miles faster; there are also parts of Florida where the speed limit is 70mph and the flow of traffic is 80-85mph. In each case, a strict adherence to the posted limit is dangerous as you now become an obstacle everyone else needs to evade.

The inverse is also true. If there are adverse conditions on the road that warrant the flow of traffic to 30mph under then going the posted limit you also put yourself and those around you in significantly higher risk.

If you're traveling at the posted speed limit and there's a broken down car stopped in front of you, do you strictly adhere to the posted limits straight into an accident or do you adjust your speed to that of the flow of traffic in accordance with the conditions of the road?

Traveling with the flow of traffic makes you more predictable and puts you inline with the actual realized conditions of the road, and being predictable on the road is the safest thing you can do while driving.

Wearing a mask makes everyone safer. Speeding along side a multitude of other speeders makes all of you safer.