That's ridiculous. It's not used to piss you off, it's used only in context to describe someone assigned to the gender they identify with because writing cis is quicker.
I do not identify with the gender I am assigned by people around me.
As this has been said before, by someone who is better with words than I am, here is a quote:
^"I do not identify with being silent
I do not identify with being pink
I do not identify with being soft
I do not identify with being scared
I do not identify with being weak
I do not identify with being submissive
I do not identify with being irrational
I do not identify with being hysterical
I do not identify with being bad at maths
I do not identify with being unintelligent
I do not identify with being followed
I do not identify with being grabbed
I do not identify with being assaulted
I do not identify with being raped
I do not identify with being inferior
I do not identify with being a woman as society has created it.
I do not identify as cis. I am not cis. I am a woman trying to fight with every fibre of my being against everything that my “gender identity” tells me to be. Woman as defined by society is not my gender identity. My gender identity is fuck this oppressive bullshit, and let me be a human fucking being".
—
Week Feminist - A Pox on the Patriarchy^
I am not cis.