By all means, set ground rules for your community and stick to them. Requiring registration and banning hate speech are perfectly acceptable tactics from the standpoint of establishing and growing a healthy online community. Shutting off the microphone is not.
What we saw with the Post is not an isolated incident. Expect to see more meltdowns along the way, as companies prepare to actually interact with their customers online, rather than address them all with the wide broadcast-model brush. Two dedicated people might suffice for responding to comments on your company's blog, but what happens when someone drops a bomb in one of their posts and ends up attracting half the blogosphere (dressed in flame-retardant pajamas)?
Much as we have redundant systems that are designed to load-balance servers and provide additional bandwidth when our Web sites experience an overload in demand, we need "burstable capacity" for the folks who actually participate in the conversation. It would help to have folks around who can help out when comments start coming in at the rate of 20 an hour when you're used to 20 a day.
But don't commit to providing a community or sounding board for people and then fail to live up to that commitment by not putting the resources toward it that it requires. That's like putting up an e-commerce site and shutting it down when you get more customers than your web server can handle. People can be very passionate about certain topics and ho-hum about others, just like they are offline. You need to be able to handle it if you somehow press a hot button and are flooded with opinions.
As I mentioned earlier, this isn't the first time I expect to see aborted attempts to cultivate and maintain community. To most of the corporate world, blogging, podcasting and other community media are things that most folks haven't figured out how to leverage on behalf of their business. As we move from broadcasting to interacting and conversing, expect to see quite a few fumbles.
As you reflect on whether or not you should be leveraging community and conversation, think long and hard about the commitment that entails. Will you be prepared to listen and respond, no matter how loud the chatter in the room gets?