I was going to recommend Patrician's Scorn! but then I decided against it because of Phyrexian Unlife...

I would argue that Fragmentize or Disenchant are both more powerful than the scorn.

SynergyBuild

As far as individual cards go you are correct both Fragmentize and Disenchant are more powerful than Patrician's Scorn, however my choice of playing Patrician's Scorn is not out of judging what the most powerful enchantment hate I can use in my sideboard is, it's more specifically targeted at a couple of decks in my current local meta where it is very good, notably the advance of R/W prison around here, a deck that has access to a multitude of problem enchantments, notably Card: stony silence, Eidolon of Rhetoric, Blood Moon, Rule of Law, Runed Halo, Banishing Light, and the list goes on as this player really focused on the enchantment side of things, not to mention U/W control seeing more play here with Runed Halo, Card: stony silence, amongst over more fringe tech. Scorn opens up a line in certain scenarios (basically when Rule of Law isn't out) where I can Angel's Grace then scorn removing any obstacle and then casting Ad Nauseam and winning from seemingly nowhere. As such for my current needs a simple Disenchant, while considered, will only serve to solve part of the problem. At a larger tournament I'm more likely to take the Disenchant as you correctly pointed out it's more powerful, but at this point in time Patrician's Scorn is the best option to deal with the problem. Thank you for pointing it out and allowing me to more fully explain the choice!