Not to quibble, but there are disorders like Asperger's syndrome, social anxiety disorder, clinical depression, and so on. Many of these would qualify the person as handicapped and therefore a member of a protected class. If there's even a doubt, you might have to settle out to avoid legal fees or a potential defeat in court. Besides, reasonable accommodations are, by definition, reasonable. Maybe he/she can be one of the people that works odd hours to avoid others?
he's bringing down the team. Sucks to be him, but if he's affecting productivity, out he goes.
There was no mention of a productivity hit. We have to take the OP at his word that he/she meant, "If somebody isn't suave or outgoing enough, fire that person." I think I'd rather educate my team about diversity, tolerance, and respect than fire technically competent people who happen to like to keep their doors closed. If you have a team that requires all others to be social sophisticates and can't function in the face of shyness, then this is your second biggest problem after handling the inevitable discrimination suit for firing Joe Shy. Also, if I worked with me, I'd probably want some alone time, too.
There are just so many things wrong with point (9) that it's hard to get them all out. Here goes:
1) Team managers, unless highly skilled (and sometimes even then) don't always understand the factors that make their teams function/fail.
2) The aforementioned possible legal liability of insisting on a team of suaves.
3) The inadvisability of insisting on a team of suaves.
4) The presupposition that the person who is awkward/shy is the problem. Maybe (the hypothetical) you and your team are a gang of unproductive dicks?
5) Maybe you're productive dicks but it will never scale?
6) The whiny intolerance of anyone who's not having absolutely the easiest time of things.
7) The fact that none of this has ever been an issue on any team I've ever worked on?
8) The insipid notion that it's a zero sum game or that the only thing is the productivity or that you can improve productivity with misguided social engineering.
I could go on. I think that what it really comes down to is that I'd rather be the guy who succeeds by helping others succeed. Entrepreneurship is as much about finding value where others can't as it is about creating new value. That includes finding it in employees who are less than socially perfect.