It is widely misunderstood as a result of people taking that small piece Jung's overall personality theory and ignoring the rest. It's the lowest common denominator tweet sized "elevator pitch" you can extract from the overall theory.

You aren't "an" introvert or an extrovert, rather you have cognitive functions that are themselves introverted or extroverted and they are ordered in your personality between strongest and weakest.

Everyone has both introverted and extroverted functions, and the opposite is always the second strongest. This is why people make up the word "ambivert." People are also confused depending on whether that function is perceptual (intuition / sensory) or judgmental (thinking / feeling), with the perceptual ones, from the meme level understanding appearing introverted.