I am not a lawyer. But OF models using O1 visa is totally fine. It is the intended purpose. The visa itself is meant for researchers, scholars who have job offers, athletes, actors etc. it has no cap and clear criteria. OF models who make a lot of money should totally qualify for this.
Also this visa in uncapped so giving visas to OF models does not take away anything from scientists and others.
O visa's original intent was to help pretty ladies from Eastern Europe to be brought into the country as indentured workers. That is why it is so easy to get this visa for an actor or a fashion model but very tough to get someone for their research.
So all this is working as intended.
Why does someone doing OF need to be in the country? You can upload pictures from anywhere.
I thought the reason for this to be a visa is because their fields' activities were in-person (acting in movies/plays/shows, academic life & research, sports training & leagues, etc). A streamer / OF worker is not like that as far as I know (but e-sports is). So this is purely to bring people with money and/or influence, nothing exceptional except the number of 0's.