Well, I'm not sure if the author is correct. I'm sure that the spammers use automated scripts and there also a lot of script kiddies, which just use the script

Well, I'm not sure if the author is correct. I'm sure that the spammers use automated scripts and there also a lot of script kiddies, which just use the script without knowing how it works. I changed to ..[at].. [dot].. email notation a while ago and I received much less spam. I'd to compare it to ssh on port 22. If you run it on the default port you will notice a lot of failed logins etc. If you change the port to e.g. 8756 you don't get any failed logins anymore, because the script doesn't scan and just use the default port.