Circumstantial evidence doesn’t need to rule out anything. It just needs to make one scenario more likely than the other scenario. Plenty of convictions have been based on that type of circumstantial evidence.The facts which people are tossing around and calling "circumstantial evidence" don't rule out anything; accordingly, they can be used to generate theories but not to draw conclusions.
Also, since apparently everyone is trying Robbi in the court of public opinion, I don’t think the “beyond a reasonable doubt” standard is applicable. People are just trying to decide if they think she cheated or not.