Collective nouns and Group Nouns

Having read this thread several times I have come to the conclusion that some things defy analysis. I cannot think of a good reason why police cannot be singular when army and navy can.

Jussive wrote:

Being as Mister Micawber doesn't seem like he's going to come back to me on this, can someone else here read my last post and say something (agree or disagree). If you disagree please point out why. Thanks

There is nothing wrong with your definition of collective noun. Grammatical terms can often be defined in several ways and the fact that people understand them differently frequently causes misunderstandings. Also, there is no point in trying to make the English language consistent and logical.  All such efforts are bound to fail.