How much of the "passivity" problems people have – about learning FI and all throughout life elsewhere as well – are that they don't want to do something and don't want to admit that they don't want to? How much is passivity a disguise used to hide disliking things they won't openly challenge?
Using passivity instead of openly challenging stuff is beaten into children. They learn not to say "no" or "I don't want to" to their parents. They learn they are punished less if they "forget" than if they refuse on purpose. They are left alone more if they are passive than if they talk about their reasoning for not doing what the parent wants them to do.
Typical excuses for passivity are being lazy or forgetful. Those are traits which parents and teachers commonly attribute to children who don't do what the parent or teacher wants. Blaming things on a supposed character flaw obscures the intellectual or moral disagreement. (Also, character flaws are a misconception – people don't have an innate character, they have ideas!)
The most standard adult excuse for passivity is being busy. "I'm not passive, I'm actively doing something else!" This doesn't work as well for children because their parents know their whole schedule.
Claiming to be busy is commonly combined with the excuse of privacy to shield what one is busy with from criticism. Privacy is a powerful shield because it's a legitimate, valuable concept – but it can also be used as an anti-criticism tool. It's hard to figure out when privacy is being abused, or expose the abuses, because the person choosing privacy hides the information that would allow evaluating the matter.
Note: Despite people's efforts to prevent judgment, there are often many little hints of irrationality. These are enough for me to notice and judge, but not enough to explain to the person – they don't want to understand, so they won't, plus it takes lots of skill to evaluate the small amount of evidence (because they hid the rest of the evidence). Rather than admit I'm right (they have all the evidence themselves, so they could easily see it if they wanted to), they commonly claim I'm being unreasonable since I didn't have enough information to reach my conclusions (because a person with typical skill at analysis wouldn't be able to do it, not because they actually refute my line of reasoning).
Joe (an adult) doesn't like something about Fallible Ideas knowledge and activities (FI), and doesn't want to say what it is. And/or he likes some other things in life better than FI and wants to hide what they are. Instead of saying why he doesn't pursue FI more (what's bad about it, what else is better), Joe uses the passivity strategy. Joe claims to want to do FI more, get more involved, think, learn, etc, and then just doesn't.
Joe doesn't claim to be lazy or forgetful – some of the standard excuses for passivity which he knows would get criticized. Instead, Joe doesn't offer any explanation for the passivity strategy. Joe says he doesn't know what's going on.
Or, alternatively, Joe says he's busy and that the details are private, and he'd like to discuss it, he just doesn't know how to solve the privacy problem. To especially block progress, Joe might say he doesn't mind having less privacy for himself, but there are other people involved and he couldn't possibly say anything that would reduce their privacy. Never mind that they share far more information with their neighbors, co-workers, second cousins, and Facebook...