I believe the trick is that they harvest "95 percent of it from the light they absorb", emphasis added. It's sort of like saying an efficient solar system only loses 5% of the energy absorbed by the solar panels.

Photosynthesis may be quite efficient internally, but it's not very good at capturing all of the available power. It really is 3-6%, where even cheap solar panels can achieve 15-20% or higher these days.

That particular stage in the hugely complex reaction pathway is hailed as efficient. The whole thing, considerably less so.

Photosynthesis is a complex process. That article only covers one step of many.