Sorry, but a violation of the public trust is still a violation of trust. Of whom much is given, much is asked, etc. I don't think you can give anybody anything more valuable than your trust.
Now, if you want to say that it's naive to ever trust a cop, hey, that's another thing altogether, but really, isn't that just as much a symptom of being numbed by abuse as it is anything else?
I'll put a good cop on as high a pedestal as can be had, but a bad cop is evil, and a schmuck cop is much closer to a bad cop than to a good one.