You asked for proof and there's plenty out there. Claiming now that the proof doesn't count because it doesn't also prove the negative is asinine. Had you asked for proof that only one side was being censored that'd be a whole different question but you simply asked for proof that the right was being censored.
Generally speaking, if you can't provide scientific evidence for something, it's not worth thinking about. Even if I were to agree that censorship will not be scientifically studied by scientists (which I do not) any individual could still try to follow the scientific method to gather evidence of such censorship. I have not seen such evidence, and every time I've previously tried to follow "plenty of evidence out there" it has not convinced me.
Ask yourself: why not follow the scientific method, publish clear data etc.? I think this is not done because it would show that such censorship doesn't exist beyond what is usually expected of social media. If you have a different reason (or even data?) feel free to show it!
I've told you my terms, and you're not going to convince me to move off my standards. Either engage on those terms, or please just save both of us the time and don't engage.