I saw that as well. As far as I can tell, it's mostly terrible reporting. They're basing it off a scientific report. As follows:
The production of Swiss-type cheeses with a typical number, size, and distribution of eyes is a difficult task, especially when bactofuged or microfiltrated milk is utilised. In this study, the potential of microparticles (plant origin) to influence eye formation in cheese, was assessed. Eight experimental Emmental cheeses were produced with one replicate from microfiltrated milk with addition of 0.0625–4.000 mg of powdered hay to the milk (90 L) and ripened for 130 days. Eye formation was quantified by means of X-ray computed tomography (between 30 and 130 days). The contents of fat, water, citric acid, lactic acid, and volatile carboxylic acids were determined at 130 days. The results demonstrate that microparticles of plant origin act as eye nuclei that control the number (P < 0.001) and size of the eyes in cheese in a dose-dependent manner. The findings also provide new insights into the formation of eye defects.
So essentially, it's not that you don't need CO2-producing bacteria. They're necessary. It's just that they need nuclei. These can be provided by mechanical holes. This is why you press under whey, so that you have fewer, larger holes. What particles do, and it doesn't have to be hay, is provide nuclei for eyes. This does not mean that more nuclei=better. It means that there's a certain ratio that would probably be ideal. If there are too many particles, you have lots of little eyes. No good. If you have too few, there won't be enough eyes. You still need the PS. It is an interesting thought.
thoughts verified by linuxboy