The sad part is he's not actually trolling. He genuinely believes this stuff.
Trolling is getting, out of people, a proper reaction, Not whether or not he believes it.
An atheist can troll an Islamic forum and so forth...
Further, I feel that if they(a troll) stir up just enough trouble, they can be an extremely positive thing(I'm not trying to infer Victor to be that positive thing, simply that he has the potential, like any good troll.) Though it's easier(and therefore more likely) for a troll to do nothing positive.
On a side note--you're an NFP, aren't you? Attaching emotional motivation to everything (especially in total ignorance of context) is usually a good tipoff.
I am inclined to believe that emotion is the basis for action(it begets intent[ensues dualistic thinking{possibly a superfluous additive}]). Your output action, based on said intention, may, or may not, pattern in a polarized fashion to underscore said emotion(based on whether or not you're meting out a deceptive filter[which is not necessarily a bad thing]).
...(especially in total ignorance of context)...
This is play by play of what I had seen(at the time):
Victor's tertiary Ni (he is ISFP) goes absolutely nuts when it comes to Islam. ...
An attempt to disassociate him from the group(naming him 'S' to a predominantly(supposedly) 'N' populace, as a matter of discredence.(I hadn't yet perceived explanation for your conclusion of his typing[I even went so far as to do a short query for the answer, but found only one quick reference to he as an ISFP within the last couple of months(I think), by you, that didn't detail an explanation within a page or two of said post. Perhaps a more in-depth search would have done me better.].)
<Victor is a fluffybunny!>
Cannot deal with views presented, and/or disagree profusely. Further, unnecessary pejorative language indicates emotional attachment to this person(posts are blockable if you care enough).
Speaking for the group in this manner, from how I've come to understand, is an emotional reaction. It also posits that you care.
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Curious thought though, an 'I' with a strong 'N', could easilly output any characterized pattern, especially with trolling in mind. This is why this sort of thing(mbti or typology in general) is supposed to be decided for self only, because of the flawed impositions of others, based on ignorance of context(though we are totally precluded from that, as we know what's up[so to speak(wink)]),...