I think it's because the "they are just characters!!" mindset is often times the only thing that prevents the FL's feelings for the ML from advancing too fast – especially in cases like this one where she is known to strongly like the character before getting isekai'd. I generally understand it when it's a sudden isekai situation instead of a reincarnation, since they adapt less to the life of their "new identity" (so to speak)... but even then, it's truly something that gets way too old way too fast. It's usually just handled very cheaply too even though it COULD have some nice introspective moments, RIP...
I totally agree with how she’s already lived here over a decade, why does she think the world will just “end” when this is reality.
But for the last paragraph… well, people write real person fiction in our world too. Plenty of celebrities have to face the fact that internet strangers imagine what their sex life looks like. And people also write and ship BL in places where homosexuality is illegal (like China, where you can go to actual jail for writing BL). It’s a weird and complicated parasocial situation.
Is it smart of a prince’s fiancee to write smut of another prince? No, and it would cause a MASSIVE diplomatic incident for sure. But people in real life have done dumber things, so I can’t say I’m that mad about it.

My one problem with the girls in these stories is that they know they died but it still feels like they don’t treat the people of that world as real.
Like our girl knows she’s died and has been living as L (I don’t know how to spell her name) for what 16-17 years already you only got some past life memories because of how great that nightmare most likely shocked you. So what I’m not understanding is why do you think the world is going to collapse when you already know you died and that these are real people. Because her saying the otome world is going to collapse like girl let it and just live your life. Like girl these are real people and not ones behind a screen the sky is not about to fall on top of you lmao.
Also because they are real people I find it a little weird that she writes/draws bl and nl about these different princes/princesses from other countries but I always find it weird to imagine real people in those type of scenarios tbh. Also, maybe because I’m so cautious the fear of any of them finding out would keep me from doing any of that other than lite talking because could that not cause and international incident especially because how that Fire country completely abhors and bands homosexuality and she drawing BL of them my girl is truly fearless!!!!