Alison Bechdel has been worried about selling out for decades. Not selling out of books — the award-winning graphic novelist has more than enough to go around — but selling out to capitalism for the sake of comfort. The specter of compromising artistic ideals, activist fervor and queer identity to the maw of the monoculture ran through Bechdel’s groundbreaking queer comic strip, “Dykes to Watch Out For,” as it built a loyal fanbase in the pages of now-defunct gay and lesbian newspapers. The layers of intellectual insulation that characterize graphic novels like “Fun Home” and “Are You My Mother?” serve to distance Bechdel from the family whose secrets she’s publicly exploring. Her newest book, “Spent: A Comic Novel,” has no choice but to admit that “selling out” is now just selling. The consumer critique of “Spent” is one that punches primarily sideways, highlighting how readily Alison betrays her own high ethical and political standards and how reflexively she uses an intellectual gloss to rationalize the betrayals. The 25-year run of “Dykes to Watch Out For” …