It never should have been 'designed' as a block in the first place.
The fact that it's narrated as preventing action rather than inflicting harm has no bearing on the fact that the intended result is to remove a character from the conflict. That is the effect of a Taken-Out result.
The subject of the block isn't taken out of the conflict and can still act, though, if the block is strong enough, they would be well advised to act in ways not covered by the block, possibly building up enough assessments, maneuvers and declarations to get themselves out or at least continuing to influence the conflict, albeit in a circumscribed manner.
A simple zone barrier could have the same impact in the right circumstances, delaying the conflict until it could be overcome, that is no reason to model it as a zone attack.