The whole conversation from the vegan side has been that those proteins and other substances essential to cats are already commonly synthesized for things like animal feed or even human energy drinks. Your own source says it's impossible without synthetic supplementation, but the deleted comments from that dumpster fire were specifically about synthetic supplementation.

I'm not an expert in this stuff but I can see when comments aren't actually engaging with arguments from the other side, which is why I think that the vegans have the better argument in this whole saga.

From your source:

There are some commercial vegan diets available which have synthetically made nutrients to replace those found only in animal based ingredients.

The discussion is about commercial vegan cat food, which had the nutrients cats need, just sourced without killing other animals. The science on these diets is still relatively new, but early studies are looking pretty good.

are you kidding me?

no?

It could range from literally anything to "yeah so wouldnt it be funny if we fed cats vegan food, lol that would be so silly" to "we should force feed every cat in the world a vegan diet"

There is VERY large difference between the two. Like i said, i wasn't there, i didn't read the thread, but it didn't sound super excessive. It seems like the current rule is they can talk about it in the explicit context of research and data, but that seems a little strict to me, as it ignores the philosophical, ethical, and moral implications of it, it's hard to determine whether that's something you should or shouldn't do if talking about it is literally banned.