1. Police officers are people under an intense amount of pressure in a dangerous line of work. Ability to dissent from police is good - abusing police really, really isn't. The vast majority of police are really nice people, and will work with you and help you on a wide range of things. Like in other professions, some cops suck or are incompetent to varying degrees, but most are pretty good sorts. The officer's report from the Gates incident had Gates coming out onto the street and yelling more after Gates had left his home. I don't know at what point yelling at police officers starts getting in the way of that work, but there is that point somewhere.
2. The article did gloss over it, but yes, it is really impractical to get hostile to anyone that has power over you - even including the electric company. People are people - you remember the last time someone was seriously a jerk to you? Remember how you felt? Now, do you remember the last time it happened in relation to your work? Would you say you worked harder to please that person afterwards, or would you say you held at least a bit of an "F you" attitude? That's just a practical point. Police officers are people. They undergo training to react more sensibly and less emotionally, but they're going to react way more friendly and cooperative with people who are friendly and cooperative with them. Yeah, sure, it shouldn't be like that. I guess technically an employee at the electric company should work doubletime to get your power back on even if you're cursing and raising your voice at them and calling them names. But the world doesn't work like that.
So many places like to list every police misconduct incident in the last xyz years every time something happens. They don't mark down or just pay lip service to all the lives saved, and all the officers killed in the line of duty doing good work. Police and citizens are fundamentally "on the same team" - less tension and more respect between both groups would be a good thing. Articles that go hard to one side don't promote that.