Vegan catfood products are on the market, so whether or not they are good for cats, they have been approved by several regulating bodies

Yeah, that's not how it works. Especially in countries with extreme regulatory capture like the US.

Unless a product has text that says in a very specifically worded way that it's been tested and approved by a relevant regulatory body, it hasn't.

The fact that something hasn't been taken off the market YET does not necessarily mean that it's been approved. Especially not when you're dealing with politically volatile stuff that could lead to lengthy public lawsuits sapping the resources of the already chronically underfunded and understaffed agencies.

If it's vegan food for obligate carnivores, it MIGHT technically be "safe" (as in won't be outright lethal), but for the reasons you yourself mentioned, it's likely to significantly decrease the animal's enjoyment of life at best and more likely to be downright torturous.

It would be like going into a vape community and banning accounts that claimed vaping is safer than smoking

Except for the fact that those accounts would be absolutely right and have reams of scientific evidence from the world's foremost experts in related fields to back up their claims. Unlike the people abusing cats in the name of not abusing animals.

it probably isn't

It is. It's not even anywhere near the next city over from the neighborhood of close.

but I don't need admins deciding who gets to have discourse about that

Except limiting the spread of dangerous misinformation, such as common myths that are keeping smokers away from one of if not THE most effective smoking cessation tool, is a big part of what admins are FOR.

if you're dumb enough to take veterinary advice from an internet vegan group, you're probably too dumb to keep a cat alive anyway

Yeah..that's not a valid argument either. A lot of vegans avoid getting a cat because they're too overzealous in their veganism to even want carnivorous animals to eat meat.

The Venn diagram of people vegan enough to love carnivores but refuse to give them meat and people who would trust a vegan online echo chamber more than competent veterinarians is a circle within a bigger circle.