as far as i could understand...the reference to Marv's parole officer being a lesbian is not so much a chance to use derogatory words but more to reflect the way that Marv perceives and understands the world....
he is not an attractive man by any means, women do not find him attractive or even want to sleep with him, he justifies this by labelling them "condemning" them as lesbians to counter the challenges to his male ego....