Anti-Humanism represented a form of speciesism embraced by certain extremist alien groups. Frequently, but not universally, it emerged as a response to Humanocentrism.
Similar to other forms of speciesism, adherents of anti-Humanism ranged from moderate (simply disliking Humans due to their species) to extreme (engaging in violence or advocating genocide). A prime illustration of the latter was the Diversity Alliance, an anti-New Republic terrorist group that plotted galaxy-wide Human genocide through the deployment of bioweapons.
The existence of Anti-Humanism likely dates back to the Republic's inception in some capacity, although it gained greater prominence during and following the Imperial Era, as a reaction to the Galactic Empire's own speciesist doctrine of Human High Culture. The Hutts were one species known to hold long-held anti-Human sentiments. Bothans, including prominent Senator Borsk Fey'lya, often displayed anti-Human biases and alienocentric views.
Despite the Rights of Sentience, the New Republic's governing body experienced the influence of anti-Humanism to some degree, demonstrated by the appointment of Senators with anti-Human sentiments. Chief of State Leia Organa Solo faced repeated discrediting attempts from alien representatives based on her species, and certain alien factions lent support to the Diversity Alliance against the Solo children, who were detained for "illegal" entry into Ryloth in 24 ABY. Years later, when Organa Solo attempted to warn the Senate about the impending Yuuzhan Vong War, she faced accusations (from alien Senators) of attempting to reinstate Human dominance over the galaxy.