I think you did hit on a key point about Jerks. People spoiling to ruin it for others on purpose.
What's not talked about much (and there's parallels to other subjects), are people who some chunky time after a release get angry that we spoiled Fight Club for them. This is akin to the folks looking for offense which muddies the waters on actual offense. I suspect this falls back to the Jerk point. Somebody going into a Fight Club room who hasn't seen it is there to be a Jerk when they raise that flag about a spoiler.
Well, this brings up a separate issue that I touch on in the above post, but didn't want to get into fully. The entire reason I did a deep dive into this subject was because someone that I very much respect was taking a very strong anti-spoilers position in a different thread that I couldn't understand, so I thought I might get to a better understanding by doing a deep dive on the issue.
Fundamentally, I think that many people tend to fall into default positions on spoilers based on upon assumptions about spoilers; in effect, they are viewing it from the position of someone
deliberately spoiling things with bad intent; on the other hand, I think that others view this as people discussing things that have been out for a while and believing that they should be able to discuss them without worrying that someone, somewhere, may not have seen it.
Admittedly, I had trouble understanding the first point of view until I went back and saw how much (and how often) people had weaponized spoilers; I had a vague recollection of that, but didn't fully appreciate it until doing the research.
Which led to my more nuanced position which I think accounts for the objection- that weaponized the trolling spoilers are always bad, but people should be able to discuss things (especially those things that are relevant to popular culture and well-known) that have been out for "a while" or are "generally known and referenced" without others complaining about it being spoiled.
Finally, I did come across research that suggests that while people believe that spoilers are bad, enjoyment is actually increased when you know what is coming (because of cognitive dissonance, or something like that). The reason I didn't include that in the OP is twofold-
1. I think it's disingenuous to tell people who avoid spoilers, "Ha, you don't know what you really like." Not just disingenuous- kind of obnoxious.
2. It didn't seem like the research had a very large sample size or had been replicated. I am leery of these types of social science nuggets that haven't been replicated yet.
That said, it would be interesting if true.