You've misread FIAT, and missed the nuances. You're completely incorrect with your assumptions regarding 'Sicklers' and trait carriers being 'sickly' and how and for whom Nicosan was designed.
Trait carriers aren't in need of Nicosan, and Sicklers don't have the immunity that trait carriers enjoy vis a vis Malarial infestation, as you aver.
There is no point in discussing Nicosan, or SCD without very basic and correct understanding. People who have SCD are born with SCD through chromosomally indication. This is the low coefficient end of the genetic mutation. Those who are exposed to Malaria, who are not genetic trait carriers, are subject to Malarial infestation.
Btw, "sicklers" is a term frequently used to describe an individual, a human being, a person, suffering from Sickle Cell Anemia, "Sickle" - therefore the reference. We all know it doesn't mean "sickly"