Cissexism

Cissexism is a form of sexism, specifically, a way of thought in which only cisgender people are seen as normal or right. Cissexism is harmful to all kinds of transgender people, including non-binary people.

Casual cissexism
One form of this prejudice is casual cissexism, which often takes the form of an apparent "honest mistake," forgetting that anybody other than cisgender people exist. For example, resources on sexual health often give the idea that all women only have one kind of private parts, and men another. The resource fails to talk about the exceptions to this rule: transgender and intersex people, and in cisgender people with medical conditions. The people who wrote the resources didn't mean to leave people out. They just didn't know any better, or they forgot. It was an honest mistake, with no ill intentions. However, it was a mistake nonetheless, which can make trouble and do harm. For trans people, that resource might be no good, or worse than nothing.

Casual cissexism is common in language, and one way to address it is by taking up gender-neutral language.

Micro-aggressions
Cissexist micro-aggressions are small offensive things done and said toward transgender people, with intention and ill will. Though they are small, and might only be words, they can be so frequent that they can become overwhelming to transgender people.

Nonbinary erasure
See main article: Nonbinary erasure.

Another specific form of cissexism is Nonbinary erasure, the common but wrong idea that there are only two genders. This comes with the expectation that everyone should fit into only one of the two parts of the gender binary. This can result in discrimination against people with non-binary gender identities. One way this problem can be addressed is by working for visibility and recognition of non-binary people.

Nonbinary erasure is connected to dyadism, the belief that there are only two sexes, and biological essentialism, the belief that one's body is what permanently makes somebody who they are.

Binarism
See main article: Binarism.

Binarism is a form of racist discrimination based in nonbinary erasure. Western culture typically erases nonbinary and transgender identities. As a result, Western colonialism puts pressure on other cultures to conform to its own form of the gender binary, based in white norms. This includes discrimination against gender roles unique to other ethnicities.

Trans-misogyny
See also: Wikipedia's article on Trans-misogyny.

Trans-misogyny, or transmisogyny, is sexist discrimination against transgender women. Julia Serano made the word for her trans-feminist book, Whipping Girl: A Transsexual Woman on Sexism and the Scapegoating of Femininity (2007). By far, trans women of color are targeted by more and worse transphobic hate crimes than any other transgender group. Trans-misogyny is such a big problem because a patriarchal society-- by definition-- has contempt for womanhood, femininity, non-conformity, and gender variance. A patriarchal society sees a trans woman as a combination of all that the society tolerates the least. It is important for any activism for transgender rights to think of how their work could include trans women.

Misdirected misogyny
Misogyny is a form of sexism, specifically discrimination against women. Some misogyny ends up doing harm even to people who don't identify as women, because others see them as being like women in some way. This can happen to non-binary people, transgender men, and gender nonconforming cisgender people. That is called misdirected misogyny. Calling discrimination against men "trans-misandry" assumes the existence of "misandry," which is disputed. A patriarchal society can make misery for people of all genders, even men, but the ultimate source of that misery is the patriarchy's contempt for womanhood, not for manhood.

Solutions
See main article: Activism.

Cissexism of all kinds can be addressed by means of activism. This activism can work to make visibility of transgender people, fight for their legal rights and recognition, defend victims of transphobia, and so on.