Like many workplace practices, it's something worth trying, but not something to be trumpeted as "the way" to do things. Some people get on with pairing, some don't. And it's OK either way. Likewise, there are writers who work in pairs, but many who do great work alone. There are architects who work in groups and alone. So it goes for software developers.
Where it goes sour, however, is when people who find pair programming valuable start tarring anyone who doesn't do it as being error-prone slackers.