And even in the case of mathematics proofs, that tells you nothing about things such as: extendability, taste, where future direction should go, what this philosophically means, etc. Which we definitely do care about.
It's funny because the people throwing around fallacy accusations everywhere don't understand that they are semi selectively using fallacies alongside claiming universality while not actually practicing it (not that you have to, of course, I very much don't agree with that premise, but if you're the one saying it...)
Anyways. /rant, it's crazy how many people don't discuss these basic but subtle ideas. To be fair, I struggled with the same exact things when I was 15, and it doesn't seem like you get taught this kind of nuance until maybe the tail end of a rigorous bachelor's degree, though personally I only learned this stuff on my own through extensive trial and error and suffering.
Yes, but we all have insufficient intelligence and knowledge to fully evaluate all arguments in a reasonable timeframe.
Argument from authority is, indeed, a logical fallacy.
But that is not what is happening here. There is a huge difference between someone saying "Trust me, I'm an expert" and a third party saying "Oh, by the way, that guy has a metric shitton of relevant experience."
The former is used in lieu of a valid argument. The latter is used as a sanity check on all the things that you don't have time to verify yourself.
If someone anonymous says "Using coding agents carelessly produces junk results over time" that's a whole lot less interesting to me than someone with a proven track record of designing and implementing coding agents that other people extensively use.