I think he's talking about flat games that were converted to VR like FO4. Partially it's because in VR you get to look at objects and textures from closer by so you notice lack of detail more easily.
Partially because a lot of these ports are just inexplicably shittily made. (Like FO4)
Partially because certain engines and rendering pipelines just don't work that well on low res VR screens (like the notorious shimmering in UE4 games)