Like I said in another response.

There is a penis and there is a strap-on. The two drawings in question depict an actual blowjob and the author lamenting that the real thing wasn't as good as their imagination because in reality, you can't feel someone sucking on a strap-on.

It is objectively hardcore pornography. This is the wikipedia page definition of what hardcore pornography is "Hardcore pornography, or hardcore porn, is pornography that features detailed depictions of sexual organs or sexual acts such as vaginal, anal or oral intercourse, fingering, anilingus, ejaculation, and fetish play. The term is in contrast with less-explicit softcore pornography. Hardcore pornography usually takes the form of photographs, films and cartoons"

Gender Queer absolutely meets the definition of hardcore pornography. It depicts a penis going into a mouth.