Here is a good definition of an Internet Troll ::::
https://en.wikipedia.org/wiki/Internet_troll
From the link :::
"A Troll is a person who sows discord on the Internet by starting arguments or upsetting people, by posting inflammatory, extraneous, or off-topic messages in an online community (such as a newsgroup, forum, chat room, or blog) with the deliberate intent of provoking readers into an emotional response or of otherwise disrupting normal on-topic discussion"
There only a very few on AB, but its fairly obvious who they are. One of the ways of identifying them is that they rarely, if ever, add anything of value or interest to any debate. I certainly have no intention of naming them, but they generally self-identify, so I don't need to give them any more publicity !
They are rather like Anjem Choudary, in that they know exactly how far to go, without actually going that extra millimeter and get themselves banned.
As I have said many times before, best ignored.