Some do...a whole lot look down on both though. In the Marine Corps I had protestors at the base gate spitting at me and shouting profanities and in law enforcement we get "racist this, racist that" on a regular basis. No matter how you do those jobs, some just won't like what you represent.
I'll agree with that.
I think it has a lot to do with what side of the fence you're on when you're observing.
I have quite a few friends who served in Iraq or Afghanistan during the first half of the campaign. Their experiences with Middle Eastern culture varied greatly from mine, despite the fact that we were in those countries at basically the same time. I was simply living there among the people as a civilian, while they couldn't walk around anywhere without representing something that had negative overtones to lots of folks. They covered themselves from head-to-toe in symbolism. I was just some dude in a sarang (most of the time)... We have disagreements all the time about what life is like out there because our personal experiences, which are all valid, are almost nothing alike.
The same is true of most populations, depending on personal (and impersonal) History with the symbols of roles of the "occupying force". For inner-city kids who have been brought up with a long history of even perceived injustice, the response to a police uniform isn't going to be good, on the whole. And if that's your beat, for example, as a cop, I can also see how that would impact your feelings towards the populations that you're made to service. It could make even the most positive person become jaded after a while, I think.
But that still doesn't excuse the abuse of power, when it occurs, right?
A marginalized population already knows that they're marginalized - being constantly reminded of it does nothing to solve the root of their angst. Whether you're a citizen of an occupied territory, a kid whose older brother's friend's friend once got beat up by some good-ol'-boy Po-Po for going 10 over the speed limit, or a member of a police force that is greatly outnumbered by the populations that they're serving, the only way to ease any of those tensions is through personal immersion and cross-cultural interaction.