Because introverts are comfortable with silence, we're sitting ducks for chatterboxes. We are good listeners, or at least appear to be, even if we have retreated to our happy place in our minds while the other person prattles.
But finding some individuals boring is not the same thing as disliking people in general or finding everyone boring. It's about losing control of our scene, about being intruded upon. There's absolutely nothing wrong with finding our own thoughts more interesting than a long story about someone's husband's niece's gum surgery.