I agree with your second paragraph, but I'd like to provide different reasoning - yes, certain aspects of body type are indicators of fitness and survivability, but that's only considered attractive in modern society. A few hundred years ago, skinny people were viewed as undesirable because they were poor and couldn't afford food. Now the people who can't afford healthy food are overweight. But being overweight isn't unattractive to everybody. Some people have unconventional "types". Some people have perfectly conventional types. Some have no type.

Her main assumption (and yours) about sexual hierarchies is that everyone has a type, and that statistics can effectively predict what everyone's type is. That's not true, as nobody has a purely identical sexuality as someone else, so no amount of statistics can predict what or whom someone is sexually attracted to. Widespread, uniform sexual selectiveness is neither the result of social pressure nor evolutional markers of fitness; it just doesn't exist. There simply is no widespread uniformity to sexuality.

Thing is, that's already widely accepted in western public discourse, especially within social circles that would be inclined to read this article in the first place. Basically, this article isn't philosophy, it's reaffirming the beliefs of its likely readers, while decrying a problem that is already in the process of resolving itself.