Brian Weatherson blogged about people who refuse to leave their email address when commenting. He gives evidence that it doesn't lead to spam anyway, so one of the main objections to leaving your email address is removed. Then he qualifies it by noticing that his own case (which is his evidence) involves leaving a web address, which is usually what shows on the comment. Thus the email address isn't vulnerable to the spammers anyway.
It seems to me that you don't even need to concede this much, if your MT settings are set properly with a spam guard feature that's built into the software. When someone slides their pointer over the link to someone's website or email link on my blog, all you get is a link to something on my own blog that forwards the clicker to the correct site or opens up an email message with whatever software is configured for email. Thus email adress harvesters can't get anything from my blog anyway unless I've included any addresses in actual posts. People have nothing to fear spamwise by leaving their real email address in the comments. Yet it happens.
This set me to wondering why people go anonymous anyway. Some people have blogs with information they prefer to keep private but don't mind discussing anonymously out of a need to discuss it somehow. That's fine. I know people who do this, and I understand it. When they have a regular pseudonym and visit regularly, I can identify them by their pseudonym. If it's someone I know who doesn't mind my knowing their pseudonym, and if I acknowledge that and agree not to reveal who they are, as has happened with me at least once, I also see that as fine. Those aren't the people I'm wondering about.
It's the people who show up once, leave rather unthinking and harsh comments with fake email addresses and fake names, and never return who really bug me. Why do people do this other than to be annoying? I can't conclude much other than that they're moral wimps and won't stand up for what they appear to be endorsing. They want to register that they don't like what they see on my site, which is their prerogative. If they have something intelligent to say about why they don't like it, then I'm happy to discuss it with them and hear why they don't like something I said. If they don't fit into the first category, then even these people may be subject to my objection. Are they unwilling to stand up for their own view, assuming they really believe it? Are they embarassed for something they think is true? This is just something I don't understand.