The rules are specified in the Terms of Use, which is agreed to by every player when they register an account. While the rating system and the enforcement methods may not be adequate, it must be observed that ratings are enabled solely for the purpose of player entertainment. They should be viewed as a means of motivation to participate in competitive play, yet people consider their rating to be important and are willing to violate the Terms & Conditions to safeguard it.
Reading the above, you might argue that it supports your argument. True, ratings are for the amusement of players. But they are nevertheless meant to reflect the skill of the given player, this aids match creation between unacquainted people and gives a rough estimate of the "top players" - always a hype in games.
Of course one might still maintain that it is not a "big deal". Yet the fact remains that the Rules are laid down in the Terms of Use, rules which are there to be respected. If a user violates a rule - and one of significant consequence - without receiving a punishment then what of the other rules? Are they of any consequence if one violation was not met with retribution?
3-day ban was distributed to parties involved in this "rating shaving" issue. @wing is pardoned but there is no reason why DoctorOrgans or even Aristol should be. Artificial adjustment of ratings is a ban offence, they may consider themselves lucky to have gotten off lightly.