Riya isn't actually a racist, she just hard trolls everybody.
If you read through her content to completion. (And I mean every fucking letter, no skimming. I'm talking Fenoxo Reading level 7 here folks.) Then you realize she actually has a soft spot for her Ausar boss, and makes a pretty big effort of keeping all her comrades alive, no matter their species. Hell you can have half breed babies with her, and she's pretty "chill" with you in the nursery, (Kinda has Sera syndrome with it being a safe space for her, but Riya less so).
My favorite thing to cite is the Riya Christmas event where Riya, very "happily" (consensual resistance till top bitch is established) gets dommed by Grence, her Ausar boss. SOME HOT SHEET there.
Riya puts up a front, a facade if you will. Now if you want to make a 35k essay about why she's like this, cause I imagine you would, be my guest. But all in all, her attitude boils down to one thing, Franks being Franks, and Franks lowkey making fun of 4chan. (Do not quote me on the 4chan thing, that part changes like the wind.)