You need to read the definition of "spam". It is "in bulk"... not this.
So because I only get one message about enlarging my member it is not spam?
How many times have you said those sentences? Once, every 5 minutes, for 50 minutes is 10 times. Does 10 count as bulk?
Also, I would remove the website from the chat. I bet that is what is causing the issues. What if a player can not read English, they would still know what a .com meant, and the UI would be in their native tongue...