I have never met a trans person who confuses those intentions, I have however met cis people who say things in a rude and accusatory way.
Regardless of the inaccuracy of the meme, I'll give you the basics:
Gender and Sex, while influenced by one another, are not the same. Sex is about your physical characteristics (organs and junk), and Gender is about your role in society. Gender is how you present yourself and what makes you happy! It's different for everyone, but that's the simplest way I can put it.
I hope that was helpful! 💜