SMTP Permanent errors (550) ... why retry?

I sent a message and received it back after two days with a permanent error. I was curious why a message with a permanent error sat on the mail box for so long. So I enabled smtpclientdebug on server’s notes.ini and resent the message.

The router is receiving a 550 response:

15/05/2008 11.01.20 [0248:0005-10D4] SMTPClient: ReceiveResponse: 550-111.222.333.444 blocked by ldap:ou=rblmx,dc=bellsouth,dc=net

15/05/2008 11.01.20 [0248:0005-10D4] SMTPClient: ReceiveResponse: 550 Blocked for abuse. See Currently.com - AT&T Yahoo Email, News, Sports & More for information.

Then I asked the router to show me the queue (te router sh queue) and got this:

Msgs State Via Destination

1 Retry( 2) SMTP  BELLSOUTH.NET (Push)

                  Last error: SMTP Protocol Returned a Permanent Error

                  Next retry: 15/05/2008 11.51.28

Now the router realized this was a permanent error, so why retry?