Heteronormativity

Heteronormativity refers to the establishment of heterosexuality and traditional gender roles as the norm in society. In other words, it assumes that "normal" people are by default straight and everyone else is willfully deviant or in self-denial. This can lead to the marginalization of and prejudice against those in the LGBTQIA+ community, kinky folk, or anyone else who does not identify with traditional sexual identities or gender expression, including straight people who do not follow old-fashioned gender roles in their relationships. The term was coined by social critic Michael Warner in 1991.

Good allies reject heteronormativity.

Bad allies and enemies think "normal" is a much better label than "straight," and go on to say that tolerance is much easier when you don't have to think about it. (Bad allies say things like "thinky" is hard and argue for trans*-exclusion.)

A related term is cisnormativity, which assumes that everyone is cisgender in the natural order; this can lead towards the marginalization of transgender and non-binary people.