phishing email forwarding

I find it odd that when I receive a suspect phishing email and attempt to forward it as an attachment to abuse@cox.net or phishingreport@cox.net; I get the following error:

"An error occurred while sending mail. The mail server responded:  5.2.0 ozef1w00M4qm8we01zefaX This message was undeliverable. This message has been found to be a potential spam message, and has therefore been blocked. Please visit http://ww2.cox.com/coxagainstspam for more information.. Please check the message and try again."

It seems strange to me you would deliver it to my email address, but not allow me to forward it to you or other entities, abuse or phishing address's so it can be properly handled. 

I also get this error message if I attempt to forward the suspect email to the Federal reporting agency (spam@uce.gov) or if I can determine the company that has been spoofed, ex. (spam@docusign.com, fraud@ups.com, etc.).  If we are not allowed to forward suspect emails, what is the point of having spam/phishing support sites?