They decided to add new items, which are cool and all, but a majority of PvPers today probably don't care about that.
Think about what makes Minecraft good: options, freedom, a non-railroaded experience. When Mojang changes what's already there, people get angry. Sometimes it works: bows used to rapid fire and now they have more dynamic properties, and although you could make that argument for swords, the update mostly nerfs them in exchange for... slower clicking? That's what everyone's subconsciously thinking: they standardized PvP instead of just adding on to the strategies that our community designed.