We propose equity-focused institutional accountability as a set of principles to organize equity, inclusion, and diversity efforts in computer science organizations. Structural inequity and lack of representation of marginalized identities in computing are increasingly in focus in CSCW research – and research institutions as well as tech organizations are struggling to find ways to advance inclusion and create more equitable environments. We study humor in a computer science organization to explore and decode how negative stereotypes create unnecessary and avoidable barriers to inclusion and counter efforts to creating a welcoming environment for all. We examine the humor embedded in sociomaterial artefacts, rituals, and traditions, and uncover the stereotyped narratives which are reproduced in formal and informal spaces. We argue that these stereotyped narratives both pose a risk of activating stereotype threat in members of marginalized groups, and of normalizing and reproducing ideas of who belongs in computer science. We situate and discuss the complexity of institutional accountability in the context of a traditionally participatory and collegial model of governance. As a way forward we propose three principles for an equity-focused approach to accountability in computer science organizations: 1) Examine organizational traditions and spaces to critically evaluate challenges for inclusion; 2) Normalize critical reflection in the core practices of the organization; 3) Diversify and improve data collection.