The Humanists were an organization of Terrans and other humans living in multicultural communities of the Federation, lobbying to segregate non-human beings and stop alien immigration on Earth. While the date of their beginnings as an organized movement is unclear, they grew into a sizable political force by the 2380s, when notable humans in other organizations, including Starfleet, fearing the suffering of human cultural pride and racial identity, had joined and fueled the Humanist cause. Terran business magnate Kwanzai Hiro and Starfleet captain Esteban Maroto were both members.
Despite accusations of racism (denied by Humanist leaders), the Humanists eventually grew so powerful that they influenced Earth's secession from the Federation. In the wake of an invasion of the Federation by the Usurpers--a rallying factor for the secession--this significantly weakened the Federation, causing it to collapse by the mid-2390s. Neria April, being a witness to these events, traveled back in time to the year 2380 and altered history with her father Stephen April's help, preventing the collapse. Though successful (thus relegating the post-2380 sequence of events to an alternate timeline), the Humanists remained an influential force throughout the 2380s. Nina Black's mother expressed Humanist sentiments in 2386. (Star Trek: Arcadia)
First appearance: "The Thing of Shapes To Come" at Star Trek: Arcadia (list 2)