And yes, speed limit laws, do change over time.
And no, you can't be punished for having broken a speed limit in the past, that is not in effect today.
Parent's comparison seems rather apt.
If society A says the speed limit is X and society B it's Y and society C it's infinite. What's the point that speed is objectively measurable?
Society A and society B won’t disagree on whether something is moving at 150km/hr.
It is more like this, person A is in a hurry and is allowed to drive over the speed limit because person A is good person, but person B, who also is in a hurry, is a scumbag and therefore person B is not allowed to drive over the speed limit. It is very similar to how woke culture works.
Please detail how we can objectively measure “offense”.