Public opinion is slightly different. It's trial by public when there is no sufficient evidence to at least rules out rational probability.
As in she says vs he says with both withholding evidence until it's released in the court proceedings. This is trial by public when based on either he says or she says the public condemn a person. Example is Antony, where no solid evidence that can point in either direction. These kinds of incidents merits an innocence until proven guilty
Mason case on the other hand, we already seen enough evidence to beyond reasonable doubt accept that Mason is guilty. When I say reasonable is common sense, not mental gymnastics such as doctored evidence or explanations that goes beyond common sense like roleplay
If Antony case has taught us something is that evidence and accusations are hard to fabricate, let alone using doctored or photoshop. It's very easy to debunk when the evidence is false.
Mason is not trial by public perception. It's as simple case as it is. Any other explanation or defence will be up to Mason to provide, which he hasnt been able to produce up to this time. Hence the public rightly decided he did what he's accused off. Anyone who has watched enough hollywood court procedural would tell you that all testimony would be cross examined, including the timing of the incident, the doctor report, where you were during the alleged incident, and there would be all kinds of evidence to proof if you're lying or making up things. It's not as simple as providing pictures of a bloody nose and yell he did it. There would be cross examination, setting the facts right, and at any time either one of them is lying or showing discrepancies the case could be over before it begin. The burden of proof in actual court is quite high compared to simply providing evidence. You have to actually back them up real good.
So the two incidents are different, and rightly have different outcome.