I think this is a fascinating discussion. I know several police officers, and have great respect for them and the service they provide. I have encountered a couple who did not represent their departments or their profession very well. They were the exceptions in my experience. I say all of this to say I do not have an ax to grind with law enforcement. They often have a thankless job to do in very demanding and dangerous situations. Thank God for them.
The challenge that many LEOs seem to have is they can get cynical in their world view, and many tend to see through a dark set of glasses. They can get an "us versus them" attitude that makes for distrust, esp in the more crime ridden neighborhoods. A forced entry raid is a very dangerous situation where there is no margin of error. Get it right and everyone goes home for dinner; get wrong, and officers or innocents can die. With the stakes so high it is incomprehensible that the wrong house can be targeted. When it does happen everyone involved is culpable, and should be held accountable.
In the case of Barnes v. State of Indiana that Webleymkv posted the court found: We hold that there is no right to reasonably resist unlawful entry by police officers. For those of us who tend to take a libertarian view of government, this very problematic. In fact it is more than a little frightening.
"Any fool can criticize, condemn and complain and most fools do." Benjamin Franklin