There are plenty of facts there to be outrage about. Was he legally allowed to use the device while driving? Yes, but that doesn't mean he was legally prohibited from stopping before using it. If the nature of the communication was such that it was reasonable to give an immediate response, then pull the fuck over and respond. It's not like he's in pursuit of somebody. Just pull over, give your immediate response, then continue on your way.
Second, "the narrow roadway curved slightly to the left without prior warning"? Without prior warning? How the fuck does it do that? So he looked at the roadway, he sees it is perfectly straight, looks away, and then the road suddenly reshapes itself to curve slightly to the left? If the officer needs to look away from the road, he should first
1) get a good look ahead at the roadway
2) Identify any obstructions that may be coming up (such as parked cars, traffic cones/barricades, etc)
3) Identify anything or anybody that might get into his way in the next several seconds
Only once he's done all of the above and decides he's almost certain to be in the clear for the next several seconds, THEN he should look away, but not for more than a few seconds at a time. Even that is risky, but for anything more than just a few seconds, you absolutely can not know what you are about to encounter (unless you are on some divided highway in the middle of nowhere with few cars, and no entrance ramps around). He most certainly should NOT be looking away long enough for him to travel more than the distance he can see ahead. If he didn't see that curve, then either he didn't look very carefully ahead, or he had his head down for a VERY long time.
I also have issues with the guy having worked there for 16 years and not being familiar with at least the major roads. I understand he works for the county and not the city, but still. I think I can do better than that for the roads in my county, and I don't have a job where half the job description is practically 'driving for a living"