Raven isn't on Salem's side, she's just not on Ozpin's either.
She's a neutral party focused on survival. Abandoning her own child is terrible, but in the context of the story she is not an antagonist or even villain at the moment, just a terrible person.
Survival by any means necessary; 'shady' alliances are no exception.
Qrow seems to think Raven has the Spring Maiden. If that is the case then she is not allied with Salem as Salem had Tyrian hunting the Maiden down. If it isn't, Raven still asked Qrow if Salem had the relic, something she would proabably know or have little to no concern if she did. If it was a lie, they could have easily used more ambigious language that doesn't make Raven look like she is concerned about the power Salem possesses.
We have no reason to believe Ozpin's going to get his own body, and Raven is pretty much as morally grey as this show's likely to get.
You want RT to get sued by Netherrealm???
Do you actually know what the word "antagonist" means? Here's a hint in case you slept through english lit literally every single year: it's not the evil people.
Ark, you're basically telling Mike there that Raven is antagonist material.
One example: Death Note. The protagonist is Light, who uses the Death Note that he found to start magically murdering any and all criminals in the world. The main antagonist is L, a famous and highly skilled detective who has been called on to help track down the identity of this murderer who has been nicknamed Kira. In that story, law enforcement are the antagonists, and a young man who has taken it upon himself to murder all criminals in the world is the protagonist.
Simply put, the protagonists are the characters who the story follows, and the antagonists are the characters who stand in opposition to the protagonists.