I'm watching one of their streams right now. It says "playing Tibia" at the top of the page.
Cause there isn't a Zezenia section on twitch and if you didn't have it tagged under a game how would anyone find your channel?
It's like if I played Tibia and streamed it under WOW, no one would say "THIS HAS TO BE WOW IT'S UNDER THE WOW TAG!!!!!"