That figure isn't correct. For the same amount of suspension travel (vertically), a vertically mounted shock travels exactly the same amount. If that same shock is mounted at 45 degrees, the shock compresses ~1.4 times farther than the vertically mounted one. And 1.4 times faster. Since shocks work on a compression velocity principle the shock mounted at 45 degrees will have more resistance.
45 degrees is the sweet spot, and the compression distance decreases if mounted closer to horizontal. In the extreme, if a shock is mounted horizontally, it will have zero compression as the suspension compresses.
