The "few bad apples" argument has to be retired, or we have to come up with a new definition for the word 'few':
Farrar and his small police force have become the poster boys of body-worn cameras...
...the year-long trial period ending in February saw an 88 percent drop in complaints against police and a 60 percent reduction in uses of force by the police. And these steep declines occurred even though the cameras were in use only about half the time.
http://nymag.com/daily/intelligencer/2013/08/nypd-cameras-rialto-farrar-bloomberg.html
In 2011, New Yorkers were stopped by the police 685,724 times.
605,328 were totally innocent (88 percent).
350,743 were black (53 percent).
223,740 were Latino (34 percent).
61,805 were white (9 percent).
341,581 were aged 14-24 (51 percent).
http://www.nyclu.org/content/stop-and-frisk-data
The Los Angeles Police Commission is investigating how half of the recording antennas in the Southeast Division went missing, seemingly as a way to evade new self-monitoring procedures that the Los Angeles Police Department imposed last year.
http://thefreethoughtproject.com/lapd-cops-disabling-recorders-cops-either-them/
Criticisms against the entire police force are not generalizations, they are backed by empirical data.