It's not only the "new" users who can be accused of jumping in with the insults and stirring the pot . there are plenty of long-time, long-winded members, who are more than capable of doing that, in fact, they're better at it, because they've been doing it for longer.
Indeed; some long time users can be rather trying, this is true.
Actually, on a related matter, another issue I have noticed is that of some who have become quite expert in the fine art of tendering borderline insult and who specialise in petty trolling, some of whom have an exceedingly finely calibrated nose for where the line is in deliberately giving offence.
In truth, it can present quite a bit of a challenge to call them out on it.