I had a totally different reaction to Joel's post. He seemed to emphasize shaping corporate culture deliberately in positive ways, rather than letting things happen by accident. He emphasizes creating a positive social environment in the office: welcoming new people and promoting inclusivity.

It seems like you mostly object to one line in Joel's post:

when new people start work at the company, they’re not allowed to sit off by themselves in a corner

I agree with you that it sounds a bit Draconian. But I don't think that was Joel's primary point. It's more of an implementation detail. He's contrasting his efforts with other environments, where people don't naturally get included. Point being, by deliberately defaulting to inclusion, corporate culture can be improved. You might disagree with his implementation technique, but I think his objective is noble.

The overarching risk Joel is highlighting is the risk of "programming by accident" applied to corporate culture -- as is done at many companies.