Those are two different analyses.

Were a culture war influencer to decide that speed limits were anti-freedom, that would not make speed limits themselves ineffective.

Compliance would surely suffer in one certain country, meaning the imposition of speed limits would lose effectiveness. That could warrant exploration of alternative implementation, policing and especially communication, I grant you that, but there simply is no alternative measure.

I get the appeal of holistic analysis, but you're throwing the baby out with the bathwater. What else can you do?

It's not that hard to drive safely. It's not that hard to wear a mask. I know it's not convenient, but statistically speaking you're unnecessarily killing people.