I think the whole point here is that By The Time You HAVE A Name Tag (Written), you've "dealt with" probably at least a dozen (more likely 100's, if from Chest, Loot) Creepers. "Brainwashing" Hostile Mobs - turning them into "Zoo creatures" - is sort of like the Killer Bunny Rabbit.
Extremely rarely found /done (in Vanilla, un-Mod'd'ed, Game Mechanics), except when it is, it's Really Funny (and /or scary). It's just a choice, of how-differently, one wants to Play the Game, something MC excels in, being a pseudo-"God," Sandbox -style(s) Game.
And yeah, this specific Original Post(er) is about the Game Difficulty being set to "Peaceful," only, and some would argue it's more-unfair /hostile (to the Hostiles) to have them Despawn-on -contact (easy ex.: Elder Guardians; which-then don't Respawn). Wolves to Players in regular non-Peaceful is one thing, but Name Tags are actual valuable /valued Loot (or at least I know I never Trade with Villagers, for them, preferring the challenge, and rarely-naming stuff, mainly Horse-types).
And I know, this all sounds so-much like "Brainwashing." Heh, but if it's possible, it might be worth exploring.