Diane Forsythe and other feminist scholars have long shown how system builders’ tacit assumptions lead to the systematic erasure of certain users from the design process. In spite of this phenomena being known in the health informatics literature for decades, recent research shows how patient portals and electronic patients health records continue to reproduce health inequalities in Western societies. To better understand this discrepancy between scholarly awareness of such inequities and mainstream design, this study unravels the (conceptual) assumptions and practices of designers and others responsible for portal implementation in the Netherlands and how citizens living in vulnerable circumstances are included in this process. We conducted semistructured interviews (n = 24) and questionnaires (n = 14) with portal designers, health professionals, and policy advisors. Results show that in daily design practices, equity is seen as an “end-of-the-pipeline” concern. Respondents identify health care professionals rather than patients as their main users. If patients are included in the design, this generally entails patients in privileged positions. The needs of citizens living in vulnerable circumstances are not prioritized in design processes. Developers legitimize their focus with reference to the innovation-theoretical approach of the Diffusion of Innovations. So, although feminist scholars have developed important understandings of the exclusion of citizens living in vulnerable circumstances from portal design, other academic efforts have profoundly shaped daily practices of portal development. Diane Forsythe would likely have taken up this discrepancy as a challenge by finding ways to translate these insights into mainstream systems design.