Heterosexism is not the same thing as homophobia,
just as
Antisemitism is not the same thing as fear of Jews.
See:
Readings for Diversity and Social Justice : An Anthology on Racism, Sexism, Anti-Semitism, Heterosexism, Classism, and Ableism. Edited by Maurianne Adams, Warren J. Blumenfeld, Carmelita Rosie Castaneda, Ximena Zuniga, Madeline L. Peters, Heather W. Hackman.
Young-Bruehl, Elisabeth. (1996). The Anatomy of Prejudices. Cambridge, MA: Harvard University Press.
Noël, Lise. (1994). Intolerance: A General Survey. Translated by Arnold Bennett. Montreal: McGill-Queen's University Press.