(EN) Why do I have to validate myself to enter the computers of the computer rooms?

Computer classrooms -

The National Security Scheme (ENS) requires the identification of users who access the electronic resources of the Public Administration in order to guarantee the security and privacy of the information of the users themselves.

Art 16 of the Regulation on Information Security: establishes that access to information systems must be controlled and limited to duly authorized users, restricting access to the permitted functions.
Regulation of use of ICT resources art. 5.1: Assignment and use of Resources: The University of Valencia must provide users with an access account consisting of an identifier and a password, through which they can use the ICT resources for which they have been enabled. In addition, art. 5.3 says that the user is responsible for the actions carried out through his account, which requires him to identify himself in the use of ICT resources.
Art.8 of the Regulation on the use of ICT resources develops the principle of responsibility, so identification is fundamental.

More info:

http://administracionelectronica.gob.es/ctt/ens

https://www.ccn-cert.cni.es/ens.html