Hey wolf, the security code is at the bottom to make sure: people are logged in, and are actually part of the website (a member/user etc). Also, it prevents robots (accidently and sometimes on purpose) adding messages which aren't useful (such as long lists of code etc)
Basically, its a safety precaution to help the website. I know its annoying and sometimes hard to read, but thats better then having spam on our forum.