Your opponent pushes the nash range, not a particular hand.
Calling nash against a nash pushing range is neither +EV nor -EV, that's the definition.
Deviating is -EV.

You're thinking of the EV of the some random hands playing all-in. Well, that's random, it's about the EV of your decision.
If you take a specific hand and your hand has >50% equity you call (+EV), if it has <50% you fold (EV=0).

Every time you guys type or say +EV, think in comparison to what.

When you shove HU, your opponent has a range, you don't. You have a specific hand.

Imagine you are HU, 15 BBs no antes. Imagine your opponent is calling 100%. Nash says shove 54s. But it will be -EV in this instance. Of course our opponent is playing a losing strategy overall, but not when we're dealt 54s.