The concern here is that romance novels encourage women, particularly young and impressionable women, toward views that reinforce gender inequality. The concern is not that readers mix up reality and fantasy. Rather it is the belief that readers are subconsciously attracted to a latent message in the books that subverts feminism. Unless they read a lot of popular fiction, academics are unaware how much variability there is in sexual explicitness. But I understand part of their point here.
Romance novels contain much more explicit sex than mainstream fiction and other fiction genres.
Several sympathetic academics have mentioned how uncomfortable they are with the objectification of both male and female bodies found in these books, and not just on the covers. The portrayal of Native American heroes in Westerns is the most troublesome example. Points 1 and 2 are easy to refute. But points 3 and 4 are difficult to deal with, because so much of the meaning read into romance novels is in the eye of the beholder, and cannot be quantified. It is useful to remember that academics are an elite too, and read meaning into popular fiction based on their own points of view.