So whats makes a city employee so much more special? Unless there is a specific reason that s/he would need to there, or course. Victor pays this person's salary (and the mayor's) - they should not have priority over anyone else.
Since City business affects all of the people who live and work in that City, it can be reasonably argued that a City truck can park wherever necessary to accomplish that business, because the City serves the common good. That truck might have been parked there for good reason. One logical reason might be that the truck required a wider parking space, and a handicapped space would fill that need. But, since the City establishes and enforces the parking codes, it can also suspend them for City vehicles, when necessary, to accomplish its own work. Parking in a handicapped spot does not endanger the public welfare, so it should not be viewed as a terribly serious offense on the part of a municipality.
If public officials can take the time to respond to all complaints or requests that would be good for public relations. But, given the demands on their time, it is simply realistic to expect them to prioritize these matters. If a matter is truly urgent, one should expect a fairly prompt reply. However, Victor's complaint was not an urgent matter. It was not an ongoing problem. It was not even an inquiry into why that truck was parked there. It was simply a letter of complaint about a City truck that was occupying a handicapped spot on one occasion. And his first e-mail was not worded in a way that suggested a reply was necessary.
Handicapped parking spaces are a privilege and not a right. No one is guaranteed a handicapped parking space, no matter the nature of their disability--the first ones to get there get the available parking spots. Maybe that City truck should have been parked there, maybe not. Either way, it did no more than briefly inconvenience Victor, just as if that spot had been taken by another handicapped driver. As a handicapped person myself, I fail to see why this incident should cause the mayor to treat this as a matter of the utmost importance.