[1] In 1971, alongside fellow writers Juan José Sebreli, Manuel Puig, Néstor Perlongher, and Héctor Anabitarte, Matamoro co-founded the Frente de Liberación Homosexual (FLH), one of Argentina's first organisations advocating for the rights of LGBT people.
[2] Matamoro’s community of advocates faced significant oppositions from the Argentine dictatorship, as their advocacy for queer people went against Christian ideology, to the point that his partners were repeatedly captured and tortured.
[3] Olimpo contained a number of messages that were dangerous to the ideology of the dictatorship, particularly the intentional humanization of many famous Argentine figures, such as Hipolito Yrigoyen and Juan Peron.
[5][page needed] In terms of violation of Christian morality, Matamoro fought the argument that homosexuality occurred as a result of abuse, a lack of a strong father figure, or the idleness of wealth.
[2] He was editor of Cuadernos Hispanoamericanos of the Spanish Agency of International Cooperation (Agencia Española de Cooperación Internacional) and collaborated in diverse media as literary and music critic.