We have a list of terms and/or characters that is used to automatically filter out contact information. I am assuming that the at symbol has been added to this list but it is in there for the best interests of the site.
It was more by way of a comment as have noticed several people said about the censorship without giving out personal information, and as it happened to us a couple of times went into edit to find out why & found out the reason - so for other peoples info too. Dont use the at symbol