It is illegal. As an artist, if another individual or company wants to use my work for their own commercial purposes in any way, even if just to ‘analyze’ (since the analysis is part of their private commercial product), they still need to pay for a license to do so. Otherwise it’s an unauthorized use and theft. Copyright doesn’t even play into it at that point, and would be a separate issue.
Yet what these companies are doing does not constitute ‘fair use’, period, no matter how much you want to argue otherwise.