Fundamentally, my position is about what art, as a product, is to me and what I find valuable.
Much like a handmade "artisanal" crafted kitchen knife, hand-knit scarf, or homemade meal made by a loved one; I receive greater personal enjoyment and benefit from the product knowing that it was made individually by a skilled crafter. Part of that is the effort or emotion put into the process. Part of it is the challenge. Part of it is definitely the ethical associations I make with the purchase ('am I supplying someone with a living wage?', 'what do I think about the corporation behind this product line?', etc.).
Perhaps it speaks to my rather economically pampered position in society that I can afford to care how the things I purchase are produced*, but for many of us who will never likely have to worry about starving to death, it's going to be a major distinguisher between products will want to buy and those we won't. Probably more and more so if technology continues to make society sustainable on a fraction of the total population working in existence-vital roles** and the creative arts might end up being an avenue to keep everyone else employed***. At some point (I think we're approaching it now), art that someone actually has to sit down and create with paint and brush is going to be luxury product simply by virtue of the effort and challenge required in the making (that was kind of true already for things we buy in the form of prints as opposed to the actual canvas, given how much can be accomplished by completely non-AI digital editing).
*but then on the other hand in the discussion of art (much less art in leisure pass-time books) we're inherently pretty far down Maslow's hierarchy of needs.
**and we prevent the waiting cataclysms waiting on the horizon
***if that's a goal
Regardless, I don't see buying AI art to be 'unethical' -- it is a tool, after all, and so long as the tool is being used by another vendor who also will use the profits to feed their family and whatnot they seem ethically equivalent to me. However, I do see it as a lesser product, same as I would if I found out that my handmade artisanal kitchen knife was a cookie-cutter product with no effort or my loved one had served me takeout they pretended was theirs.
I will say that I'm not particularly convinced that AI learning from the wealth of human artistic creation being equivalent to artists learning from the an existing body of artistic knowledge and tradition. The reason is that art, specifically, is something I consider a form of communication. It's not some kind of 'soul' I am looking for, but cognition and awareness and existence as a societal being. The intentionality is part of the product. I've found sunsets and wilderness scenes and even patterns of color in parking lot water from leaked engine oil that are prettier than some art that I've seen, but there's still a distinction between the two (sometimes even when I'd rather frame the oil spill if it could be preserved).