The truth is that I translated the ToS a long time ago, and every time Discourse changes something, they put them back in English, so I got tired, hehe… It’s not an easy task to translate all the ToS into Spanish.
Here is the discussion to talk about the ToS in Spanish: Términos de Servicio (tos_topic.body) 🇪🇸
I created a complete repository so I wouldn’t have to start from scratch every time Discourse updated the terms: https://github.com/SidVal/SidV/tree/master/discourse
If you want to join the Transifex team to help with each translation, you are welcome.
Here I explain how you need to join: https://meta.discourse.org/t/como-traducir-con-transifex/104566
Update: @absi, I have checked the ToS on Transifex, and they are indeed translated. Which Spanish language variant are you using? 
Do you have the latest version of Discourse?