First of all she is hiding and possible not even within Russian border. So no clue where your idea of political protection is come from. And there is little point in arresting her: there are far more people working on project and nothing going to happen if public face going to disappear.
What's more important it's can be tough to actually prove she actually did something illegal on her own. Of course for political activists there is no evidence required to put them in prison in Russia / Kazakhstan, but she is pro-Kremlin so it's not apply here.
"For her actions in creating Sci-Hub, Elbakyan has been called a hero and "spiritual successor to Aaron Swartz"."