I don't really have a problem with this comic. Actually I've thought a bout this thing for a while and I don't understand some of the issues people have with it.
It says we're essentially female: Uhm, that's not how I read it. It says one time we're physically speaking essentially female. Now while that isn't the most gentle or pc way to put things if you started arguing with clueless straight guy as put in the comic saying that a vagina isn't female per se, even physically speaking will get you nowhere. Then the comic proceeds to say: I only date men (so clearly he considers us male), some of the guys I date have a vagina (so yes, we have that part that's a reality it's not the word most of us like to use but it's there, yet as he says that doesn't make us any less men).
It makes a big deal about the penis: uhm, I read it as pointing out that people make a big deal about the penis but that really it's not: as he says there are lots of other parts that are important, and if his hot boyfriend likes it he'll like it too and that you know things can be helped, whatever, it's all good.
Lastly the whole not attracted pre-testosterone, attracted post-testo and being attracted to short guys (he points out: okay, that's defensive, yes I like trans men): I'm attracted to certain things as well. I'm pansexual so generally these things have nothing to do with gender or sex, but I for example prefer the lean muscley types to the big muscles. No this isn't the most important thing, but the short guys... I mean if he likes that and is attracted to it he's likely to end up with those. Most of us are quite short, it's not like he's saying he likes transmen because they're short he's saying that might explain why 3/4 of his last relationships were with a trans guy. And most of us look prepubescent pre-T so I mean,... It's not wrong to start a relationship based on pysical attraction is it? If he happens not to notice most pre-T men that way (trans or not really) is that such a big deal?