It's one of those fundamental truths that they expect you to accept without proof.
What it really is is bigotry.
Most people don't believe that crap. It is a noisy few trying to sound like they speak for a lot of people. Watch the screen names. It really is very few.
Saying a government system is bad/broken/corrupt is not the same thing as saying gun owners are bad because a few do bad things..........
He's right, it is a generalization. What I've realized is that they're playing something very similar to the race card. What they're trying to imply, as a form of
ad hominem attack designed to discredit the arguer, is that generalization must mean the person is speaking about
all cops, which must mean they're bigoted, which must mean their opinion is merely a product of prejudice.
But it doesn't work that way. There's nothing wrong with generalizations in and of themselves. They may be right, and they may be wrong. The only time a generalization becomes
prima facie invalid is when it is phrased in such a way as to apply to
all members of a group.
Let's consider a few examples, shall we?
Generalizations without merit:
• Black people are criminals.
• Southern conservatives are racist, xenophobic KKK members.
• It is always cold when it is rainy.
• Gun owners are law-abiding.
• Cops are evil.
Generalizations which do not purport to apply to every member of the group, and which may have merit:
• Black folks commit more violent crimes than while folks.
• Most conservatives oppose gun control.
• It is generally chilly when it rains.
• The average gun owner is law-abiding.
• The average cop will cover for the "bad apples" in their ranks.
I believe you when you say that on the balance you find the actions of the officer wrong, but I still think you asked for a gentle ribbing. 
