Maybe they originally had "to be viewed correctly" and then someone else found this insulting to their editor's pen, resulting in a "when viewed" but leaving the "correctly".
It does, but SteamVR, which does the lense distortion/correction, isn't FOSS. It exposes an OpenXR backend that software can use though. Their goal is to implement this part for themselves/the Linux community, so their hardware can use it without having to rely on SteamVR.
Note there is a typo at the end of the article.
> Note that the images in our VR displays still need to be distorted for them to look correctly when viewed through our lenses
I believe that should be "look correct". Look correctly I think implies that the displays are an agent doing looking.