Although research on accessibility in computing systems is a topic of traditional interest in Human-Computer Interaction and Informatics in Education, the dissemination of computing technology has required considering accessibility in an increasingly comprehensive and systemic way. This paper proposes that accessibility in computing systems must be understood as a human value, and traditional methods of interface design and evaluation must be revisited to cope with such understanding throughout the entire design process. This paper presents a practical study of accessibility evaluation for the deaf in the environment to support High School Exam for Brazilian students provided by the National Institute for Educational Studies and Research on Youtube. Results point out to accessibility problems in videos, texts, images and personalization by users, which, from the perspective of values, can trigger negative individual and social consequences in aspects of autonomy, economics, identity and equality that can not be reversed or corrected only by technical updates.