If I was a sports star in the limelight even at our level I wouldn't be on socials for precisely this reason as like it or not there are always dick heads whether they are trolls or "fans", "supporters" whatever. It's stupid and obviously most would condone it including me but the only way for it not to happen is not to be involved in the circus in the first place as unfortunately there is always one. You will never stop it unless the accountability for the action rests with the companies who own the platforms and their revenue models are put at risk. Which will never happen.