Confusion!

I continually see time written like this:  12:00 AM and 12:00 PM.  How do you interpret that?  Is 12 AM the high noon hour, the official end of the morning? Or is it the middle of the night?  And is 12 PM the high noon hour or the middle of the night?  I do not know why people continually use those designations for time because they simply are incorrect.  Just as we've become slack in our grammar, spelling and punctuation (in part due to the computer), we've become slack and incorrect in writing time.  It is 12 Noon and 12 Midnight -- it's that simple.  Why do we make things so complicated?  Any feedback here?