The American Physical Society calls on its members to improve the diversity of physics by supporting an inclusive culture that encourages women and Black, Indigenous, and people of color to become physicists. Introductory physics courses provide opportunities for recruiting and retaining diverse students or enacting policies and cultural practices that disproportionately harm students from minoritized groups. Introductory calculus-based electricity and magnetism courses have received far less attention from researchers than introductory mechanics courses. To better understand the role introductory electricity and magnetism courses play in the lack of diversity in physics, we investigated the intersecting relationships between racism and sexism in inequities in student conceptual knowledge using a quantitative critical framework. The analyses used Bayesian hierarchical linear models to examine students' conceptual knowledge as measured by the Conceptual Survey of Electricity and Magnetism. The data came from the LASSO database and included 3,686 students from 83 calculus-based courses at 16 institutions. The model indicated society owed educational debts in conceptual knowledge due to racism, sexism, or both to Black, Hispanic, Asian, and White Hispanic students and White women. Of these groups, society owed the largest educational debts to Black students. The courses, of which almost all used collaborative instruction (81 of 83) supported by learning assistants (66 of 83), added to the educational debts owed to Black students, maintained the debts owed to Hispanic and White Hispanic students and White women, and mitigated the debts owed to Asian students.