she reads stories a certain way and so assumes other people do as well

Right! Also I think part of the issue is that it can take a long time to figure out that certain types of stories are bad for you psychologically, especially if they're considered Normal. Once someone has figured out for themselves that, say, romances with rape in are bad for them, they want to save other people from having to go through the same long and painful process of self discovery. But you can't shortcut other people's processes of self discovery by just assuming they work like you! Because they probably don't!