User blog comment:Lukeatlook/Pyro's Item Overhaul 11 - The Mage Project/@comment-24420226-20150110050402/@comment-4813965-20150110172234

@PrimusMobileVzla One of Riot's catchphrases is "anti-fun" and purging buffs would qualify for that as much as the good old mana burn did. Copying buffs = fun for user. Denying buffs - not so much fun for the user, more anti-fun for the target.

It's less frustrating to have the opponent copy your buffs - which he likely won't take full value of - than to lose a crucial buff that you need.