Police are decent people ?

Some are and others aren't. They're human.

some are and some aren't.

By and large, police tend to like order, and what they view as "proper" behavior, which leads them to be a bit excessively judgmental by nature.  And they are not at all averse to solving conflict by applying physical violence.  Those things might keep the typical police officer from being everybody's cup-of-tea, but they don't make police INdecent people.

However, after they've been police officers for a while, there is a tendency for them to divide the world into police on the one hand, and non-police on the other.  And some of them come to view all non-police as either perps, or perps-in-waiting (as in "EVERYbody's broken SOME law or other").  This amounts to seeing themselves and their brothers-in-blue as a superior class of person charged with keeping all lesser people in line or under control.  Such police are decidedly NOT great to be around...but even THEY may still be "decent", in a barely-tolerable sort of way.

But like any people, there are good ones and bad ones.  No matter how hard a PD might try to avoid future trouble by hiring just the right kind of people, there are always a few bad apples that sneak in.  Unfortunately, that means we can never say "Police are decent people" because some few among them inevitably AREN'T, and we end up ashamed that we ever let them don our uniform...not to mention worried about what sort of injustices they (and by extension, WE) might have committed or abetted.

We also can't really conclude that "Police are BAD people", either - and for the same reason:  There are lots of good ones, just as there are a few bad ones.

There's nothing to be gained by wondering whether police are personally good human beings or not.  We can't be a nation of laws without them.  What we actually need to consider is whether we are choosing and employing them properly, and training them and motivating them as we should be.

Most of them are decent people.

Some of them are good decent people, but others are tyrannical sociopaths. 

Most are, but a few bad ones can do far more damage to the public trust than a few bad people in most other jobs.