Oh we CAN. The real question is not ‘Can we" but “Should we”?
“Jerk” is a subjective term. One man’s ‘jerk’ is another man’s "tell it like it is’ guy is another man’s “comedian”. It is also a term that carries a tone of nastiness. A ‘jerk’ is someone who is ‘deliberately’ obnoxious, not merely somebody like a ‘bozo’ who is clownishly obtuse, or somebody who accidentally causes a problem like a ‘klutz’.
IMO it’s better to be less ‘personal’, focusing on the actions and not treating the person with a lack of respect AS a person. Once you make a label, like ‘jerk’, you are making the person into that label of ‘jerk’ and not ‘a person who is doing X’.
Yes, there is a type of political correctness that leads to a stifling of the truth but that doesn’t mean that truth cannot be spoken. It just means that we have to take a little more time and trouble to make sure that what we say is not only factual/accurate, but is said in a way that we won’t be ashamed to acknowledge before Christ. He, you may notice, had no trouble calling certain groups of people ‘whited sepulchers, broods of vipers’ etc but was careful to acknowledge that it was the ACTIONS that caused it, why it was a problem, AND what they should do to correct the problem. And of course, the one who ‘made’ the people has a little more ‘right’ to remark about them than we do.