You’ve got to understand the audience he’s talking to and the effect he’s trying to have. It’s not a legal claim being made in a legal setting and he knows it. Instead, he’s talking to people who are motivated by outrage. It’s incredibly disingenuous and I think you stop behavior like this just by talking away the benefit he has by acting this way. So let him be irrelevant and drown him out! If no one hears they aren’t going to get outraged.