The point is that recommendations are exactly what they are.
The recommendation is "Drive no faster than 45mph on this road unless you want to risk getting a ticket (or killing someone or whatever)."
But who's physically preventing you from driving 60mph? If you were taking your dying relative to the hospital would you drive 45mph?
Perhaps a law of physics is involved and you are physically prevented from going over 45mph because of a governor on your engine, but you could pay someone to remove it (or do it yourself). Speedbumps may increase the danger and consequence of going 100mph and that is something of a physical limitation.
You can think it's asshole philosophy (and perhaps it is), but you're not seeing the world the way it really is, which I think is heart of the matter.
It's like the clip of the guy talking about the German who can't drive because they don't have a license:
https://www.youtube.com/watch?v=B3EBs7sCOzo
It's just a recommendation!