asexuality, like bisexuality, is deliberately misunderstood by out groups in order to exclude us.
asexuality isn’t “straight people who don’t want to have sex”. even the conventional definition, a “lack of sexual attraction” is not a particularly helpful or well liked definition within the community, because it obscures this fact: asexuality is a distinct sexuality. it’s one that involves a lack of primary sexual motivation, but it’s not “X but no sex”.
all asexuals are ace, regardless of their romantic orientation or behavior.
biphobes think that bisexuals are straight when they’re with someone who they deem opposite gender, and gay when they’re with someone they deem same gender. they can’t seem to separate behavior from identity, to get that someone is bisexual regardless of their sexual behavior.
likewise, aces are ace regardless of our behavior. aces aren’t “straights who don’t have sex”. for one, because some aces have sex (because people have sex for a lot of reasons other than attraction). two, because to be straight is to possess sexual attraction. that’s why, historically, asexuals have just been considered gay (and later, bi). whatever the True Gays think of us, the straights don’t make that distinction.
this is why if your acceptance of asexuals is limited to same-gender-romantically-attracted aces, you don’t actually support asexuality. you support someone you consider “a gay person who doesn’t want to have sex”. because all aces are ace and asexuality is queer.
this is the same raw deal bisexuals get. I suppose if you can, as a group, even fathom attraction the outwardly perceived opposite gender, you can’t be True Gay ™. (which is probably why such a high proportion of trans and NB people id as bi, queer, or ace.)