Cops go WAY over their obligation every day to ignore mouthy citizens and rude ones and mean ones and verbally abusive ones.
You know what? So do convenience store clerks, cab drivers, waitresses, McDonalds employees, Walmart employees, and lots of other people. It's part of the job. If you can't handle it, you need to get another job. Of course people are much more likely to get mouthy with a convenience store clerk than a cop, because we all know cops kill people regularly, and store clerks very seldom, if ever kill someone.