Organisations should not have social media channels at all if they are not prepared to monitor and manage replies. This is such a BASIC failure, to let your enemies use your posts on your page to peddle their bullshit.
KnitMeAThneed
Serious plea to politicians and parties re your social media channels: just delete the hateful shit. You don't have to be a platform for bigotry. And yes, I have DONE this as a job, I know it takes effort, but if you set clear standards for your online spaces the community will follow suit.
