Hold up, you think the definition of art is too broad if it includes Photography but not broad enough if it doesn't include Generative AI? Based on that I don't think it is possible to give you a reason you would accept.
This conversation of "art" reminds me of the difference between "value" and "values": https://davidgraeber.org/articles/value-the-antropological-theories-of-value/
If someone want high quality digital art, teaching them crochet doesn’t help them.
This is a statement of "value" not "values". That someone wants "digital art" but there is no connection being made to their "values", they are simply getting what they want.
Art is not a commodity, AI is.
The important thing is that we use our standards to not engage with what is being said but to pursue purity in our information sources. We should start by disconnecting from the fediverse because you obviously can't trust half of what is being said here.