Ally is not included in the 2SLGBTQ+ acronym, as an ally is not an identity, but an action. While it can make allies feel more included, ally is a quality that is chosen and can be as visible or invisible as desired. An ally supports 2SLGBTQ+ people and communities and educates themselves about the inequities faced by queer and trans communities. Allies speak out about these inequities and advocates for change at structural and individual levels.
Allies do not face the same systemic and structural inequities that trans and queer communities do. Allies have the privilege and power to uplift and support 2SLGBTQ+ initiatives but must do so in a way that centres 2SLGBTQ+ communities and does not impose further violence on them. 2SLGBTQ+ spaces are meant to be safe and supportive for individuals, and allies must be mindful of this when interacting with this space.
The term ally is an active verb, rather than an identity to foster good feelings within oneself without doing the associated work of allyship. Being an ally is not meant to be easy or superficial; it involves deep, difficult and ongoing meaningful engagement with 2SLGBTQ+ communities.