The loudest cop-haters (in person and on the 'Net), in my experience, are those folks who are but one routine traffic stop away from an extended stretch in the Graybar Hilton.
You are right. Usually, those who hate Police I encounter broke the law at some point time, got caught doing something they shouldn't be doing, or carrying something they should not be carrying. Now, it is all Law Enforcement's fault they spent time in jail or had to pay a huge fine and court costs.