Really? They've had their heads kicked in, refused jobs, surgically mutilated, imprisoned etc because they're asexual? They have passages in holy books dedicated to hating them and wishing death upon them? They have laws criminalising them? Really, is that what you're saying?
repository.uchastings.edu/cgi/viewcontent.cgi?article=1418&context=hwlj
However, “outgroup hate” plays a central role in human beings’ social
identities.60 In a 2012 study, researchers revealed strikingly strong bias
against asexual people.61 Predictably, attitudes towards homosexual,
bisexual, and asexual people were more negative than attitudes toward
heterosexual people.62 The more groundbreaking result was that within
sexual minorities, asexual people were evaluated most negatively of all
groups, falling behind both homosexual and bisexual people.63 Further, of
all the sexual minority groups studied, asexual people were perceived to be
the least “human;” they were attributed with significantly fewer human
nature traits and were perceived to experience fewer human emotions.64
Asexual people are dehumanized by being characterized as both “machinelike” and “animal-like.”65 Because sex is so much a part of non-asexual
peoples’ lives, and because of the pervasive sexualization of our society,
those who reject sex are viewed as less than or not even human.66
As attention has increased towards asexuality, animosity towards asexual people has increased correspondingly.67 Beyond discrimination, the
most extreme form of this animus is sexual violence designed to eradicate
asexuality.68 Asexual activist Julie Decker reported that sexual harassment
and violence, including corrective rape, is disturbingly familiar to the
asexual community.69 She stated that people who carry out corrective rape
do so because “they believe that they’re just waking us up and that we’ll
thank them for it later.”70 Decker has received death threats and numerous
comments that she “just needs a ‘good raping’”—leading her to conclude
that when some people hear that a person is asexual, they see it as a
challenge.71 In recounting the sexual assault she personally experienced,
Decker said that after speaking extensively about her asexuality with a
friend, he tried to “fix” her by sexually assaulting her.72 She recalled that he
tried to kiss her, and when she rejected his advance, he pushed her against
the door, licked her face, and yelled, “I just want to help you!”
academicworks.cuny.edu/cgi/viewcontent.cgi?article=1050&context=jj_etds
Recognition is emerging that asexuality is a valid sexual orientation. This emergence shares similarities with past (and some present) attitudes toward other sexual minorities, including the attempt to label it as a pathological disorder by comparing it to sexual dysfunctions, similar to the manner in which the sexual orientations of lesbian, gay, and bisexual (LGB) people were treated as medical conditions in the past (Scherrer, 2008). There are also certain forms of societal and legal discrimination that value people who have sex (particularly heterosexual sex) over asexual people, for example, there are laws that allow for the annulment of marriages based on non-consummation, implying that a marriage isn't valid if it does not include sex (Bogaert, 2015).
I especially like that asexuality has been called a "psychological problem" on this thread confirming this research.