No Sir. Please just explain me how can referral link as part of OP be spammy and sending it via PM is not spammy? (though it increases the work unnecessarily for the person who created that thread to get some referrals and pay them)
Do you know what would happen if we let 1 person post a referral link (Note: A referral link is acceptable in a very rare case of a very constructive post/thread/contribution/other; but I'm going to disregard this now)? People would start posting their links not just in single threads, or sections, but everywhere (Note: We can't let a single person do it; it's everyone or nobody). Once that starts, they start using more accounts to post even more -> Spam. This is a chain reaction. Referral links are useless, IMO they should be disallowed forever.