I may not agree with certain laws practiced in my country or around the world - but then again, I do not agree with what a lot of people find normal and required, and shit ain't gonna change that easily.
But eh, they're just doing their jobs in most cases. Most aren't such bad folks, and in the end I'd rather have some cops then no cops at all despite my philosophies. You must understand that their lives aren't exactly great, either. I mean, a lot of us could tell a whole lot of stories of high-school teachers being - well - total bitches and horrible people... but imagine being in their place, wasting your whole life with a bunch of little shits, trying to teach them over mindless gaggle and having to read through their idiotic essays and what not.
Same thing with cops. I'd not want to be one, the same way I'd not want to be a teacher.
Also, OP, you can't really blame cops for things you said. Policemen do not make laws, and while you might disagree with state's position on drugs (I know I do), it's still there and if you choose to ignore it, you should accept the possibility of by-the-book punishment.
A rape is a rape, it can happen in any circumstance - and while a policeman might have certain advantages in terms of authority, you cannot simply blame all the police force for the deeds of one person - it's like blaming the humanity for being shit just because someone raped you. Sure, you can do it - but you're a fucking whiny ***** if you do.
And the third thing you said, probation meeting is probation meeting. So what, a birthday. It doesn't mean you can miss it, it's not grade school anymore - just because one has a birthday doesn't mean he/she can skip work (without pretending to be sick) or in this case, skip something as important as a probationary meeting.
The whole anti-cop movement is stupid. Be as anti-authoritarian as you can (and I am, to a certain degree) but policemen are just tools, nothing more. They do not make the laws, they do not forge bullshit morality and excuses, they just do their job. If anything, be against Courts/ political people/ people in general because when you see a shithole, very often it's thanks to the people who live in it.