I have some sympathy for toasty here: they're just listing ships that other people categorised as f/f, and making a note that not all the characters are actually binary gendered women. I'm not sure how I'd handle that myself. It makes sense to exclude any ships about binary gendered men, but there's no neat line between those non binary characters who identify closely enough with women that it makes sense to classify their relationships as f/f, and those who don't.