I feel you're splitting some sort of grammatical and/or semantic hair there.
Like, for instance, what is the difference between "obesity is unattractive" and "the fat are unnatractive", really.
In "altruism is unattractive", it looks like there is a rhetorical device being used known as metonymy: referring to a subject indirectly by naming an attribute or adjunct of that subject in its place; it in fact means "altruists are unattractive".
Definition of altruism:
>unselfish regard for or devotion to the welfare of others charitable acts motivated purely by altruism
>behavior by an animal that is not beneficial to or may be harmful to itself but that benefits others of its species
edit after skimming the article: Perhaps they meant to say "Altruists are not always attractive"