As most schools do with most demographics, they could first have kept the initial acceptances close to the number of actual seats they had to fill, and those initial acceptances could have had a M/F split however Emory chose. When early returns started coming in heavily favoring females, most or all of the calls off the WL could have been to well qualified males.
This is precisely how schools achieve diversity across whatever metrics they care about -- IS/OOS, race, SES, anything that can be asked about on a application. Sex is by far the easiest one to actually achieve, due to the overwhelming number of highly qualified candidates of both sexes that apply to each and every school, each and every year. By allowing it to go to a 28/72 split, Emory clearly did not care at all, at least not last year, and apparently made no effort to achieve balance.
Of course, this does not mean they actually wanted a 72% female class, so no one should infer that from the result. OTOH, it is fiction to claim that any school has no control over who decides to matriculate. They have total control, since one cannot matriculate without first being admitted, and most schools can and do use the WL to fine tune a class to its preference. The fact that Emory made no such effort indicates they are fine with 101 females in a class of 141, even if that was not their goal.