I’m honestly shocked that you attacked him/her for this. It’s a pretty safe assumption that someone who uses Internet forums (such as this one) knows what an emoji is.
It’s kind of like assuming that a person who lives it Texas knows what a tortilla is...
No, it isn't a safe assumption at all. Why would an adult know, I don't .
Have you ever pried an 8 track from it’s stuck in the player because the tape got tangled in the capstan ?