I've seen many instances where a single moderator will close a question unilaterally
There's literally no other option for us to close a question, short of getting a sock with enough reputation to close questions. Which might potentially be against the spirit of general policies on socks - since we aren't supposed to use them to do anything our main accounts can't.
A good chunk of new mods actually find this... pretty scary, and someone who apparently is a slightly more experienced moderator, I mainly use the closehammer on already cved or egregariously bad questions only.
rather than allow it to collect some answers first or even allow it to be voted on by more than one moderator.
If it's a question that needs to be closed, it should be closed. Closed questions are often deleted and it's a waste of time and effort.
But the remaining stub will inevitably waste the time of others
Roomba's meant to help with that.
Historically though, there's checks and balances against it, both above and below moderators.
If a moderator uses his powers excessively - they might have a CM look in on them (and this is very rare), and if things are counterproductive, they might get removed. It happened on Server Fault once.
Below the moderator level, 5 users can reopen a question. Editing and fixing a question throws it back into the reopening queue, and before I was a moderator (and to this day), least on my site, there's a tradition of reopening requests on meta.su - there's even a tag. It works well.
Closure isn't trolling at all, we're pruning the weak and sickly so healthy, on topic questions can grow. While we do not cut the grass with nail scissors, we also do not set entire forests on fire to kill a single weed.
It's worth remembering for most part
Now that we've handled that... let's talk about trolling, with respect to your article.
The very term "troll," in fact, has been rendered meaningless due to overuse
And you might be contributing to this
The article suggests trolls 'have a compulsion to argue online'
The SE way of doing things, ideally discourages that. Comment arguments are deleted. Mod messages are mostly standard. We build tooling and mechanisms to deal with things.
and, while I don't want to go point by point
"includes following people online and communicating and responding to them in a disruptive, hostile, and at times vengeful manner, often intending to upset or cause a negative reaction or response in the other."
Amusingly, this is something mods often have to deal with. This is definitely not what a good mod is. We do want to get positive reactions from users, and I'd much rather use education and positive reinforcement to get things better.
If we close or delete something, we don't really expect a negative reaction - the ideal is OP fixes it, it gets reopened and life goes on. At volume, I don't even think I care who posts something.
And yanno what makes me feel warm and fuzzy inside? When someone turns around a closed post into something awesome. As someone who helps run a community, while I have bad days, I want to see folk build themselves up - to learn new things, to find a sense of community, rather than tear each other down.
So there could be. It's unlikely a moderator who's a troll would last long though.