I have used craigslist a lot to both buy and sell. The only anonymous email I have ever seen is for the seller. So I am a little confused regarding these responses that state it is normal. I have even checked with craigslist and according to them when you reply to a post your email shows they do not assign an anonymous reply email.
Q: How do anonymous craigslist addresses (similar to abcde-1234567890@sale.craigslist.org) work?
A: Posters to craigslist can choose to use a temporary craigslist address to receive responses. As long as the post is still active, craigslist will relay any messages sent to the temporary address to the poster's actual email address.
Note: When you reply to a post, your email address will be visible to the recipient. If you prefer to remain anonymous, consider using an email address that does not contain your name or other identifying information.