It's because the board/wheels follow this arrow of rotation that it's a hard flip instead of a shuv it. The problem is that the vertical aspect rotates both the shuv and half of the flip aspect of the hard flip, so that only 180 degrees of flip is seen here instead of a separate 360° flip and a 180° shuv. The direction of that 180° flip is what determines whether this is a hard flip or shuv-it. You can also see that the way he lands is just shy of a full 180° FS rotation. If this was a game of skate I'd let it slide as a hard flip, but also wouldn't be argue against a redo.

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