The point is that the state needs to flip enough that Trump would not be in a position to control what the state (the court actually) views as an official act.
If Trump continues to have enough influence in the SCOTUS after he's done being president, then yes, you could imagine they contort any action into an official act. But that'd be a failure of the next government to first establish a less biased SCOTUS (either by packing it or removing existing justices).
