I'm an artist myself, absolutely love Midjourney, and have absolutely no problem with it being trained on any and all art -- just like human artists have been doing for millenia.
Long term, if Adobe is clearly worse than the competition as a result of being legally/ethically conservative they will lose users. They will get a lot of likes on twitter but companies will not pay for a firefly subscription if it's worse than Stable Diffusion.
Commentary - yes. However, if it is found that the model itself is not sufficiently transformative and including copyrighted fictional characters in it is seen as an infringing derivative work, then even though the output of it may be used in non-infringing ways then litigious companies would still have an argument about copyright infringement on the model.
Until that is settled, its likely that Adobe is taking the "we're not going to deal with any licensed properties in the model to avoid any lawsuits."
