In the trolling context:
Posters (old and new), who are posting to get a rise out of people (trolling) will be dealt with as such. Folk, in that case, are not posting an "opinion" but a "disruption". Especially with new posters, if it is the former or the latter is hard to judge. Some think it is obvious, but without fail, they have been wrong from time to time too. That why we check thoroughly, and with more tools, have more data to form an opinion around.
Who is and isn't a troll, or breaking forum rules, and what repercussions follow (if any), and when, is for the mods to decide. Partly because mods have more tools to look into claims, and have frequently found genuine posters at the end of a lot of aggression because a few were utterly convinced they could only be a troll, partly because posters who start to police the forum aggressively are adding to the disruption, partly because engaging a troll in an aggressive way makes our job of deciding who is and isn't at roll much harder.
Posters who bully new users because they have posted an opinion that has been posted before, and that is polite, are as likely to be treated as a trolling party.
If we have a troll and everyone ignored them they have no fun, and we keep clean(er) threads. If we have a genuine user they will be finding their way around soon enough, and welcoming people nudging them in the right direction will help a lot.
If we have a genuine troll, and no-one responds, the only way they can have fun is by nudging the volume up a level, throwing bigger hooks. Unprovoked, they are much much easier to spot that way.
If people target people on "their posting style", or question their "intent", the ONLY possible route is that we keep ending up discussing EVERYONE'S posting habits and forum popularity in that thread.
There are tools in place here to alert mods to the existence of a suspected troll. Mods will look at it closely, and form an opinion, and monitor the situation too. Just because people don't see an immediate visual change, doesn't mean that there isn't a lot of activity behind the scenes.
If mods are guilty of one thing, it might be that we want to be sure that we don't turf genuine posters off the forum, just to please a few, or make our lives easier. This might mean that a "probable" troll remains a wee bit longer than ideal. It is the price of thoroughness and valuing the presence of genuine newcomers. Surely our forum can handle the odd troll for an extra day or so, especially if those who are so sure don't provide endless oxygen.
We do pull our hairs out at the endless replies to an "obvious" troll that some regulars keep making. Some only play the sort of game that keeps a troll scoring hit after hit, by engaging them, every time they are confronted "in a big way". Also increasing the likelihood they will want to come back, as this is a pond with fish who love to bite.
Ignore, report, ignore some more.
If you have a genuine opinion, on topic, and keen to share: post away - but please read a thread to see if it has been dealt with already by others, before you, within reason.