transsexual is not an old fashioned or outdated term. transsexual is not a term only used by transmedicalists, truscum and transphobic trans people. you do not have to like or use the term transsexual for yourself and no one is forcing you to, however you do have to be normal about other people using the term transsexual to describe themselves and their experiences.
people still use the term transsexual, transsexual is a term steeped in trans history and trans liberation because transness is not just about the gender binary but also about the sex binary. for many people transness is inherently related to their sex and they are trying to change their sex. sex is not an irrefutable, immutable fact and the sooner people accept that the sooner trans, nonbinary and intersex liberation becomes a possibility. I hate the sentiment that gender is a changeable social construct and sex is a biological fact because sex is also a changeable social construct.
stop buying into terf and transphobic rhetoric about sex.
