Whether what he did was or was not Official Pair Programming (tm) is beside the point. Obviously, some people will thrive having to interact with a partner all day, every day, while others will wither. Requiring all your developers to work in this style is just nuts. It's like requiring all your developers to wear size 31 jeans.
I don't think it is nuts if it is clear in your hiring process. Grockit has you pair for a day for your interview (or they did a few years ago) so you can experience what it is like, and see if you are a good fit. I agree that surprising people with pairing or trying to mandate it on an existing team is unwise, but building a company upon an ethos (to the exclusion of certain personality types) is a reasonable decision.
Whether what he did was or was not Official Pair Programming (tm) is beside the point. Obviously, some people will thrive having to interact with a partner all day, every day, while others will wither. Requiring all your developers to work in this style is just nuts. It's like requiring all your developers to wear size 31 jeans.