To the academic - if your research involves non-heteronormative sexuality in any way, people in your profession will probably assume you're queer. You can affiliate yourself with LGBTQ communities professionally via queer-themed research, publication, online presence, or conference participation, while maintaining appropriate boundaries and personal privacy.
I think it's more valuable to serve the LGBTQ cause through excellent queer scholarship, than by coming out as an individual. The entire world and the academic field of psychology need anti-homophobic, anti-heteronormative research. Flirt with, sleep with, and partner with whoever you want, while you write a paradigm-shifting book about queer psychology or bisexuality or gender transgression. (I will read it!)
Yes yes yes I just finished this book last night and everything you say is true, as is Kel's comment above that the only other female character is an Insufferable Feminist Asshole who persecutes the loyal seeker/schlump Mitchell.
Everybody's piling on with Eugenides' mocking of literary theory in the first part, but what did that even have to do with the rest of the story? How was Madeleine's English major even relevant to her self-sabotaging choices after college? So she reads Daniel Deronda and The Portrait of a Lady, she writes a thesis about marriage novels, and she still can't recognize a terrible destructive relationship when she's in it! She never has a moment of self-awareness to say, Hmm, I'm being a bit of an Isabel Archer here - why am I throwing myself away on this creep?