If bugzilla receives an e-mail from somebody and the e-mail is leas that 10k in size it should put it in the comments section instead of showing it up in the e-mail list. It is a royal pain in the ass to get to see what everybody has to say about things when their comments are sent by e-mail. I know users are dumb, let's provide them with better tools.
This should be fixed in the lastest version of Bugzilla. Please reopen bug if this is still occuring.