Some of the statements I found there:
It doesn't mean you have to be a full-blown extrovert, but if you cannot get the message across to the students in an effective way then you may end up with a problem when your school starts judging your teaching future by how many students pass the standardized tests. As far as administration, you still have to be able to communicate with parents, handle students, etc.
Misconception #1: Introverts can't communicate.
This is nonsense. Of course we can. In fact, in some situations, we may communicate *better* than extroverts because we tend to plan out our conversations and seriously think before we speak, weighing all the options and ways our responses might be taken. If pushed to give immediate answers, yes, we may come out a little garbled. But the insinuation that introverts make bad teachers because they can't communicate information is nonsense. (As a matter of fact, most of the teachers I've run across who don't communicate clearly are extroverts - they would get sidetracked, ramble, and include unimportant information.)
Introverts just don't have the skills, or desire to work well with parents, kids, and other staff.
Misconception #2: Introverts don't have people skills.
This is also not true. I know lots of introverts who are extremely socially successful, and lots of extroverts who are not. That's a completely unfair generalization. Everyone needs to learn social skills from the get-go, both introverts and extroverts, and some of each will fall by the wayside.
Misconception #3: Introverts don't have the desire to work with people.
Just because we tire of social interaction faster than extroverts does NOT mean we never find it rewarding. I am going into education with full knowledge of how much interaction I will need to have with students. But, you know what? Teaching people about theater is something I'm extremely passionate about, and it is well worth the fact that I will be tired by the end of the day. Yes, there will be days when I'm socially exhausted and just want to get away, but I care about this career. I'd rather have a job that I love enough to let it sometimes drain me.
Since they're introverts, they don't care if they are well liked.
Misconception #4: Introverts are relationally apathetic.
Of course we want people to like us. Many introverts act like extroverts because they think it's the only way people will like them. (Which, according to this thread, seems to be the truth.) Just because we need our alone time doesn't mean we don't feel a need to belong. Some may care more than others, but, seriously, we have feelings and everything. I promise.
I'm bothered when people make these kinds of statements about introverts, because it means that people don't actually know what introverts are. They hear the term, find people they deem socially inadequate, and saddle them with that label, leaving those of us who are well-adjusted, social, fairly friendly introverts with this horrible stigma.
Introversion is not something to be fixed or something you can "put up with" in someone. It's responsible for making so many of my favorite people who they are. Just like extroversion, it is a gift.