And we have all seen, many times, what happens when immersion and self-insertion goes too far. They seem to take every plot point they don't like as a personal affront because they identify with the MC to an arguably unhealthy level.
Some of them seek to transcend "Karenism," and seem closer to Stephen King's unhealthily immersive character, Annie Wilkes.
Well, some of use don't fantasize about things that would put us in jail in real life.
You say you are not knocking others' preferences, but you do kink shame by accusing people who don't your preferences as "cucks." You know as well as we do that that is used as a derogatory term, just another term to accuse someone of being "less of a man," like earlier accusations of homosexuality as a put-down. Then just like certain politicians in the US, as soon as you're called on it, you claim that YOU are the victim.
From some points of view, a man who has no problem with their partners exploring is not a weak man, he's actually one who has more trust in his own strength, and the strength of his relationships to not feel threatened. From the perspective of many of us, those who insist that their LI's just wait on their shelf like a doll is a sign of insecurity in relationships. Perhaps having a fantasy of multiple passive LIs is the result of bad real life experiences, so I try not to be too judgmental, except when they are trying pressure a developer into following THEIR fantasy and none other.