It's the same thing that the feminazis and PC brigade do, label you a misogynist or a racist if you dare to question their ideology. For most people fear of getting falsely accused will make them self-censor. The Jews have been doing this pretty much ever since the inception of the Israeli state and they're damn good at it. Being labelled an anti-semite in the US is pretty much career ending, regardless of whether you actually said anything offensive or not.