Yes, I will explain the logic. Reducing the speed to 30 km/h is an easy fix. With a few strokes of the pen it is done, and there is NO HARM IN DOING THIS. It also doesn't cost a ton of money to implement. It's not like they're taking a billion dollars out of the budget to implement this.
The logic is further this... just because they are NOT tackling the big issue does NOT mean that they should not tackle the small ones. It's like saying just because City Council has not adequately addressed environmental change, murder rates, urban traffic, the unsightly blight of loud Christmas Sweaters during the holidays [hell, insert any malfeasance in here, including not tacking the bigger issue you describe] they should not address this issue.
On a logical level, just because they don't address big issues doesn't mean they should not address small ones. If we operated on that logic, we'd have to stop all global warming before we address health care... or vice versa. Good government and good leadership is not just about ploughing ALL RESOURCES toward stopping one big issue at the expense of stopping smaller ones.
By your logic, ALL POLICE should be out solving murders and stopping the drug trade and not enforcing the very rules of the road that you want, because that is the bigger issue where more people get killed.