Why the contempt for the police?

A couple of weeks ago I published a post on speeding and it garnered a few emails asking why I had such contempt for the police. I'll tell you why - and it's a three-pronged reason.
I've only had cause to deal with the police force directly on three occasions in my life.
The first time was when I was a kid - our house in the Netherlands was burgled when we were on holiday. When we came home and found a lot of stuff gone, and a busted back door, the police came out to have a look. We gave them serial numbers for big-ticket items like stereos, bicycles etc, and their parting comment was along the lines of "we'll file this but we have more important things to do than worry about burglary". Naturally none of our stuff was ever found.
The second time was when a woman knocked my off my motorbike on a roundabout getting off the M25 at Junction 9 in England. Never found the bitch - she was driving a red Peugeot, and sideswiped me from the left. She knew she'd done it - I was on the hood of her car before she dumped me on to the road and drove off. Of course nobody stopped, so I collected my still-rideable but very bent motorbike and drove to the nearest police station (before cellphones were common) and verbatim, this is what they told me : "Even if we did find her, it would be your word against hers as you have no witnesses." Never mind that even the most retarded forensic analyst would have been able to match the shape of my body to the dent on her hood, and the position of the crack in her windscreen to my helmet, and the paint from her car to the paint on my left leg, boot and motorbike frame. No - it would be her word against mine, and as such, they didn't want to even try to find her. I know the reason why, of course. I was a motorcyclist, and the UK police have a well-documented bias against motorcyclists.
The third incident was a few years ago when an American cop pulled me over because - and again this is verbatim what he said - "it sounded like you were speeding". I asked if he had radar or photographic evidence, and of course he didn't, but then he told me he didn't need it because he was a police officer, and that his word would trump mine when it went to court. He wanted me to sign and accept a ticket, so I refused on the grounds of zero evidence, told him to take it to court and left him with "good luck on that". I never heard anything back, obviously.
So yes I understand they do a hard job, and yes I know we should appreciate them, and yes I know it's trendy and hip to hate the police, and yes I know its 'a few bad apples'. But when your only three true experiences with them have been with arrogant pricks - all 'bad apples', you start to take a pretty dim view of the entire establishment.