If your character's actions only reflect what he/shebelieves (and not the player) then it's roleplay. GMs will not punish anyone because of this. So, yes, RP racism is allowed. Just keep in mind that it's been done before (and you might want to look for those threads in order to get an idea of how to approach it originally) and that Yliakum society is not a reflection of our world's and that the racial tensions we experience IRL are not remotely experienced there. So, you'll have to ask yourself: what makes my character hate this or that race? It can't be as easy as "I was taught that we are superior" because such concept is not part of the society's idiosyncrasy: people are simply not educated that way.
Does that mean there were never racial conflicts? No. There must have been only so long ago that the only thing that remains from it is the law that condemns any racial violence with death (which indicates that at some point in history it was a big deal). So if you want to RP a racist you can, but keep in mind the context and the repercussions and, most importantly, to keep IC and OOC separated.
