Here's what I see happening
1) Spoiler threads are being disrupted by a handful of people suffering from chat addiction.
2) That handful of people are consciously or subconsciously generating spatial pressure.
3) Spatial pressure in this sense means they use sheer volume to flood the chats.
4) By flooding the chats, they ensure other users get drowned out.
5) Furthermore, they tend to be highly critical of what's said in spoiler chapters.
6) That aggressive adversarial position makes them gatekeep and argue with casual users.
7) By doing this, they create a culture where an echo chamber has developed.
8) This echo chamber created a culture that supports chat addiction.
In conclusion, the real harm of this shows up in statistics. If a chat addict user makes 60,000 posts in 4-5 years, but a normal user makes 1000-5000, it shows a clear difference in the levels of engagement. The harm comes from the idea that most of those 60,000 posts were the result of gatekeeping and argument. Is it harmless trolling or is it a dangerous side of the mind of a chat addict?