Sorry for my imprecise response. The article you linked is talking about the “Vegan versus meat-based cat food…” study specifically. I was refering back to the study I referenced in a previous comment, “The Impact of Vegan Diets on Indicators of Health in Dogs and Cats: A Systematic Review.”. The systematic review is essentially a big picture analysis of 16 other studies, 6 specifically about cats. The “Vegan versus meat-based cat food…” study was not included.
The systematic review says there is not enough evidence at this point to say whether a vegan diet is better or worse. I still stand behind “there is isn’t clear scientific evidence to conclude it is inately worse”.
I’m not putting any pets on a vegan diet. First, I don’t personally follow any vegan practices even for myself. Secondly, it’s risky at this point, and I don’t have enough resources (time, money, attention to detail) to minimize those risks. I keep pets because animal shelters kill animals that they do not have the capacity to support. I can imagine others, even those who practice vegan lifestyles, would commonly cite a similar motive.
I think I can see it from both sides, but it seems situational to me. Breeding cats sounds bad. For government animal shelters that run out of resources, I think the adoption of an animal that would otherwise be killed is logically consistent with the generic vegan philosophy.