And every one of those messages you get is from a "highly professional" server administrator that never heard that the sending address in spam message is NEVER valid...so they auto-reply to the spam to at least double the volume of garbage.
The really stoopid part about having the reply turned on is the best way to set up a spam filter is to make everything look like the mail in going through normally and then
quietly toss it. Any information you give to the goof tells him to try some other way to get through.
These maroons (the admins I mean) just gotta turn on every feature so you know they're so swift they spent $15,000 on a system they don't understand a thing about.