Because the people who support this are also the ones who hate drivers and do crazy things like impose 20mph (30km/h) speed limits in cities on the main roads.

Because the people who support this are also the ones who hate drivers and do crazy things like impose 20mph (30km/h) speed limits in cities on the main roads. The point is to degrade the quality of life and force everyone into public transport slice by slice. But the HN crowd is disproportionately made up of those who think this way. If speed limits were set to the natural safe speed the road was designed for people would be far less cynical about these things.