Am sorry, but this is pure drivel. Characters in a story are expected to act believably, that is in a manner where their personality, motivations and actions can be reasonably parsed (unless the character is supposed to be literally insane) They're behaving "people-like", because as people that's what we can understand. So, "they're not people, they're characters" is meaningless objection. Their "predetermined roles" have to make sense for the "people" they're presented as.
This quite literally has nothing to do with discussed topic, which was Ian's cuck path. The ian_cuck
variable is only affected (and set) by Ian questioning Lena about dicks of her former partners. Whether he's watched Jeremy's video(s) has zero impact on availability of that choice, or the state of said variable.