There is no real artistic merit to a live-action animation, other than cheap fanservice. Film studios don't see or appreciate the story or medium for what it truly is; they only recognize the growing popularity of anime and see an opportunity to milk easy money out of fans.
The argument
The argument starts with a question about motive: what exactly is the purpose of a live-action adaptation? It does not add anything new to the story. The plot, the characters and the ending are already fixed by the source, so whatever the finished film offers an audience, it is not a new work. If the driving factor behind these movies were some artistic film-making desire, you would expect adaptations to reinterpret their material — to say something the original did not. Instead, on this argument, these movies are actually just cash grabs, aimed at exploiting fans of an anime to take their money. The evidence offered is Disney's live-action adaptations. With very few exceptions, they have been either lackluster or just plain bad. They do nothing new with the source material they have been given, and indeed sometimes make it worse — which is the pattern you would expect if the films exist to be released rather than to be made. Fans accuse the company of merely making these films as easy ways to prey on nostalgia and rake in cash, and on this reading the accusation fits the results: there is no real artistic merit to them, just trying to make money off the same thing in a different skin. A studio holding a story audiences already love has a guaranteed audience before a frame is shot, and no artistic risk is required to reach it. The same principle applies to anime live-action movies, and for the same structural reason. Studios know the popularity of certain anime; that popularity is precisely what makes the property worth acquiring. They target their fandoms and sell them an adaptation, trading on an attachment those fans formed elsewhere. In reality, they are not making something new, but rather finding a new way to make money from an old source — which is why, proponents conclude, anime should not be adapted into live-action films.
Premises
Counter-arguments
It's overly cynical to say that adaptations are just cash grabs. Yes, they're intended to make money--all movies are--but they also allow for genuine creative output by re-imagining familiar stories in new settings. Even though the article cited refers to criticisms of Disney's films, it also shows people, particularly those who worked on the films, who appreciate the art and the creative process that went into them.
Rejecting the premises
[Rejecting P1] "Adds nothing new" is asserted rather than shown, and the premise treats commercial motive and artistic intent as mutually exclusive. Nearly all film is financed commercially, so the observation does not distinguish adaptations from anything else a studio makes. [Rejecting P2] "Cash grab" is a claim about intent, and no evidence is offered about what any studio intended — only that the films made money, which is what films are made to do. Exploitation would additionally require that fans were deceived, and the premise does not allege that. [Rejecting P3] The Disney remakes are an analogy across a different medium, studio and source material, and the premise itself concedes exceptions. The reasoning also proves too much: sequels, franchise entries and stage adaptations all monetise an existing audience, and the argument would condemn every one of them. As the counter-argument notes, the same source it draws on also records the people who worked on those films describing the creative work involved.