If accessibility is the exact situation alt text is designed for, and it works for the most part, who is to blame for it not being accessible if not the person putting inaccessible text in there? Merely providing something is not equivalent to providing a good solution.

By my understanding (as a sighted person who has relatively zero experience using such features) alt text is for short pieces of text that might aid in communication of an image to a blind person. I have even less understanding on whether or not dumping a chunk of code in there would be at all useful, and I expect very few sighted persons would know better. Hence my complaint, and hence my question.

True, but I kind of get where their headspace is here. It feels like a weird jaunt to rely on alt tags for what is ultimately just simulacrum of what exists in the alt tags considering that-for the sake of accessibility-going with plain text to begin with probably makes a lot more sense.