Does Legacy’s card Heroic Interception:
Legacy deals himself 3 melee damage.
Each hero other than legacy is immune to damage until the start of your next turn.
protect Visionary’s Decoy Projection from taking damage, assuming that something is targeting Decoy Projection directly?
I do not think it does. Decoy Projection is a hero card, and is a target, thus is a hero target. However, I do not believe it is a hero itself.
I suspect you are correct.
I was confused for a moment by the discussions we’ve had about the Operative, but I think a better analogy would be a minion (say, Citizen Truth), which
is clearly a villain target without being the (or a!) villain character.