You are right, if the ACL is applied to the proxy redirection ACL, it does mean what you posted earlier.
Basically, the acl says:
line 1: deny all TCP traffic whose port is not equal to www (port 80)
line 2: deny all TCP traffic from the proxy server
line 3: permit all TCP outbound traffic
Since line 1 already deny all TCP ports but port 80, line 3 essentially means permit TCP/80.
So in summary, redirect all TCP/80 traffic except traffic from the proxy serve itself. Everything else will not be redirected.