I live in a house with three queer/poly people. Around here, people sometimes introduce themselves or others with a note about their pronouns. But if someone doesn’t, it’s okay and either people will pick up the right ones from context, or they will guess and maybe be gently corrected.
“DiD yOu JuSt AsSuMe My GeNdEr??” is not real; it’s an Internet troll parody.